Calculator Tag: Concrete & Masonry

Concrete Footing Calculator

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Concrete Footing Calculator

Calculate the concrete material needed to pour various types of footings, including pads, foundations, and piers. Get the results in cubic yards or bags.

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Ready mix averages $125 – $165 per cubic yard

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Ready mix averages $125 – $165 per cubic yard

Concrete Estimate:

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Pre-mixed Bags

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How to Calculate Concrete for Footings

Many structures from porches and decks to homes and buildings use concrete footings for support. These footings may be small and meant to support a post or column, or they may be large and designed to carry the load of walls and roofs.

There are various types of footings that you can use to support a structure, and the type of footing will determine how to calculate the concrete needed to fill it. We’ll cover the calculations for a few types of footings below.

Isolated/Pad Footings

Pad footings are a type of isolated footing that spread a concentrated load from a pier or column. They can be rectangular or circular. These footings may be used for things like decks that need posts to support the structure above; the posts sit on the concrete footing.

For a rectangular pad footing, you can calculate the volume of concrete needed for each one in cubic yards by multiplying the length L, width W, and depth D in feet, then dividing by 27.

cu yd =
L(ft) × W(ft) × D(ft)
27

For a circular pad footing, you can calculate the volume of concrete by multiplying the radius r squared in feet by the depth D in feet by pi, then dividing by 27.

The radius is half of the diameter, so if you are pouring a footing with a diameter of 4 feet, the radius is 2 feet. For smaller footings, you may want to make your calculations in inches. Rather than dividing by 27, you will need to divide by 46,660 to convert from inches to cubic yards.

cu yd =
π × r(ft)² × D(ft)
27

Continuous/Strip Footings

Strip footings are a type of continuous footing that spread a concentrated load from a wall or multiple columns or piers. They are often used as the base of a foundation to provide a solid base and lateral support from shifting.

To estimate the volume needed for a strip footing, measure the total linear footage of the footing, then multiply that by the width and depth in feet, then divide that by 27 to get the volume in cubic yards.

This is the same process as estimating a pad, but the length will generally be longer with a continuous footing.In some cases, you can pour the foundation wall or a stem wall in a single, monolithic pour. When it’s an option, this can be advantageous to reduce pour time and curing time, and can consolidate two short loads into a single load.

To calculate the concrete needed for this type of pour, follow the steps above to estimate the volume of the base of the footing, then estimate the volume of the wall section. Then, add the volumes of each section together to get the total volume.

Columns or Piers

Columns or piers are often used as the foundation for structures that need a foundation that is embedded deep into the soil. They’re also often used to support decks and porches on homes.

You can estimate the volume of concrete needed for a column or pier, just like with a circular pad footing.

For a circular pad footing, you can calculate the volume of concrete by multiplying the radius r squared in feet by the depth D in feet by pi, then dividing by 27.

cu yd =
π × r(ft)² × D(ft)
27

Thus, the volume in cubic yards is equal to pi times the radius in feet squared, times the depth in feet, divided by 27.

In many cases, a pad or flared base is necessary to spread the concentrated load from the pier and prevent it from sinking.

If you’re using a form for this, the manufacturer often includes the volume needed to fill the bell footing on their spec sheet. Then add this to the volume needed to fill the column above it.

You can also calculate this yourself, if necessary, by using the formula for a conical frustum where the base radius is R, and the column radius is r.

volume =
1
3π
× D × (r² × rR × R²)

Keep in mind that you’ll need to convert this to cubic yards, then add it to the concrete needed for the upper portion of the column.

Keep in mind that you’ll need to convert this to cubic yards, then add it to the concrete needed for the upper portion of the column.

If you’re thinking about hiring this project out, check out our guides on the cost to install footings, deck footings, or a foundation.

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Concrete Calculator

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Concrete Calculator

Calculate the concrete material needed to pour a slab, patio, footing, column, or post-fill-project in cubic yards or pre-mix bags, and estimate the cost of materials.

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Use the average width if the footing is angled

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The footings are larger than the slab.
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Optionally enter the price per cubic yard

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Ready mix averages $125 – $165 per cubic yard

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Ready mix averages $125 – $165 per cubic yard

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Ready mix averages $125 – $165 per cubic yard

Concrete Estimate:

{{total_cubic_yards}}
{{total_cubic_meters}}

Pre-mixed Bags

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How to Calculate Concrete

Concrete, which is a mix of water, aggregate, and cement, is most commonly sold by the cubic yard but is also available in pre-mixed bags.

Concrete is used for many construction purposes, including foundations, stem walls, patios, or driveways. It’s also used to fill CMU blocks or to create countertops.

It’s important to calculate the amount of material needed as accurately as possible. Concrete must be poured at the same time; if you don’t have enough concrete for the pour, the resulting installation can be weak or need to be redone.

We’ll cover the process for estimating concrete in detail below, but you can also use the calculator above to simplify the process.

Steps to Calculate Cubic Yards of Concrete
  • Measure the length, width, and height of the slab, footing, column, or other area you are pouring the concrete.If the area is complex or multiple pours are needed, break the project into smaller pieces and calculate the concrete needed for each individually.For instance, when measuring a slab that is not a simple rectangle, try breaking it into different sections and measure the yards needed for each section separately.
  • Convert dimensions to feet if they aren’t already. Conversion calculators make it easy to convert inches, yards, or meters to feet.
  • Multiply the width times the length times the height (W × L × H), or use our volume calculator to find the cubic feet.
  • Convert the volume to cubic yards from cubic feet. To do so, divide the cubic footage by 27 to get the yards of concrete needed.[1]
  • Round up to the nearest yard as most suppliers will likely not sell fractions of a yard. It is worth asking your supplier if they will sell a partial yard of material, but most do not.
  • Estimate how many pre-mixed bags are needed for smaller projects when it isn’t practical to order a truckload of concrete.The table below shows the coverage of different sizes of pre-mix bags. On average, it will take 75 50-lb bags, 60 60-lb bags, or 45 80-lb bags to fill one cubic yard of concrete.
  • Add 5%-10% additional material to account for settling, spillage, and waste.[2] This will ensure you can complete your project in a single pour without needing to order a short load, pay crew overtime, and risk a cold joint if you come up short.
How Much is a Yard of Concrete?

One cubic yard is equal to the volume of a cube with edges that are one yard (three feet) in length.

You might be wondering just how much concrete is in a cubic yard. A cubic yard is equal to 27 cubic feet or 46,656 cubic inches, or 45 80-lb bags.

Concrete Cubic Yards Formulas

Use the following formulas to calculate the concrete needed for various types of pours.

The volume of a rectangular space is equal to the length times the width times the height. For slabs, substitute the thickness for the height measurement.

volume = width × length × height

yds3 =
width ft × length ft × height ft
27
Circular and Cylindrical Areas

The volume of a circular space is equal to pi times the radius squared times the height. The radius is equal to the diameter divided by two.

volume = π × radius3 × height

yds3=
π × radius ft × radius ft × height ft
27

π = 3.14159265359

Steps

Stairs are generally poured as one complete unit. To find the volume, get the height of each step from the ground to the height of the step when looking at its side.

So the lowest step will have the shortest height, while the top step will have the tallest. Take the length and width of the top of each step, then multiply the height, width, and length of each step individually, then add them together to get the total volume for the unit.

volume = width × length × height

yds3 =
width ft × length ft × height ft
27

For more complex shapes, check out our volume calculator.

How Many Bags of Concrete Do You Need?

So far, we’ve covered how to calculate yards, but if your project is small, you can use pre-mixed bags of concrete. Pre-mixed bags are sold by companies like Quikrete or Sakrete and come in 50-pound, 60-pound, or 80-pound sizes.

Using bags can be easier than ready-mix when you have many small pours or a small project where a truck is not practical or cost-effective. But keep in mind that mixing bags on-site can become difficult if you’re pouring a large slab or many footings.

For the most part, ready-mix concrete from a truck is more cost-effective than bags and makes sense if you have a mid-size project and can pour it all at once.

80 pound bag of Quikrete pre-mixed concrete commonly sold at a home center
So, how many bags of concrete do you need?

Calculating bags is a little less straightforward since each bag size will fill different volumes. Use the calculator above to estimate how many bags you’ll need.

The table below shows the average fill in yards for various pre-mix bag sizes. Check the bag you’re using to find the exact fill-rate for the product.

Bag Size Pre-mix Bags Needed to Fill
1/4 cu yd 1/2 cu yd 3/4 cu yd 1 cu yd
50-lb bags 19 38 56 75
60-lb bags 15 30 45 60
80-lb bags 12 23 34 45

Table showing the number of pre-bags of concrete needed to fill a volume measured in cubic yards.

How to Calculate Concrete Costs

The cost of a concrete project varies depending on the project’s size and scope, your geographic location, and the type of material used.

Concrete Cost per Yard

Ready-mix concrete typically starts around $125 per cubic yard but could cost upwards of $165 or more, depending on the mix and your location. Consider that there will likely be additional fees for ready-mix for smaller projects, such as delivery or short-load fees.[3]

Cost per Bag

Pre-mix bags usually range from $4 to $15, making them a cost-effective choice for small projects.

Average price of concrete.

ready-mix: $125 – $165 per cu yd
pre-mix 50 lb bags: $4 – $8 per bag
pre-mix 60 lb bags: $4 – $14 per bag
pre-mix 80 lb bags: $8 – $15 per bag

The average cost to install a concrete slab is $6 – $20 per square foot. Besides the cost of concrete and materials, there are also labor costs for preparing the area, the pour, and finishing.

A standard brush or “broom” finish will likely be on the low end of the price range, while a decorative finish with coloring will be on the high end of the range. While stamped concrete begins with a slab pour, it is more labor-intensive to finish, so costs can be much higher.

Consider getting a professional concrete installation estimate from contractors in your area for a more accurate cost estimate.

Tips for Preparing for a Ready-Mix Concrete Pour

Much of the work to pour concrete is done before the truck even arrives at the project. You’ll need to measure and lay out the site and install forms to create the edges of a slab or contain a footing.

Plan a proper base using a gravel or stone calculator to estimate the right amount of base fill if needed.

Use rebar or fiber/steel mesh to reinforce the concrete and to prevent cracking in the future, particularly for load-bearing concrete forms. Use our rebar material and reinforcing mesh calculators to estimate the amount of reinforcement needed for your project

Ensure the installation team is ready for the installation and able to begin as soon as the truck arrives to avoid having it set up before the project can be completed and minimize idle time.

Frequently Asked Questions

The amount that a yard of concrete can cover will vary depending on the thickness of the pour. One yard can cover 27 square feet at 12 inches thick, 81 square feet at 4 inches thick, or 54 square feet at 6 inches thick.

An average load for a concrete truck is around 8 cubic yards. At a max capacity, most trucks can hold up to 10 cubic yards.

Bags of concrete are available in different sizes, which can impact how many bags will be needed to make a yard. To make one cubic yard, you would need 75 50-lb bags, 60 60-lb bags, or 45 90-lb bags.

The ratios of sand, cement, and aggregate for concrete will vary depending on what you want to do with the concrete and what your location is. A general rule of thumb, however, is to mix 1 part cement to 2 parts sand and 4 parts aggregate.

One cubic yard of concrete weighs 4,050 lbs. This works out to 150 lbs per cubic foot. You can calculate this more precisely using our concrete weight calculator.

Recommended Masonry Resources

Rebar Weight and Size Calculator

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Rebar Weight and Size Calculator

Calculate the weight and size of the rebar for your project given the length and quantity.

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Total Length

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Pounds per Foot

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Kilograms per Meter

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How to Find the Size and Weight of Rebar

Rebar, or reinforcing bar, is used in many masonry and concrete projects to reinforce slabs and structures. Because concrete has low compressive strength, rebar helps it bear loads without cracking.

Therefore, for most concrete projects, rebar is required to help the slab, footer, or foundation maintain its structural integrity. Rebar is available in standard sizes, making it easy to find the weight and dimensions of the rebar for your project.

The first step is to identify which size of rebar is being used on the project, for example, a #3 rebar. Most home and residential projects will use #3, #4 or #5 rebar, with #3 being used most commonly for patios and driveways, #4 for walls and columns, and #5 for footers and foundations.

The next step is to identify how much linear footage of rebar will be used. Linear footage is the total amount of length in 12″ increments needed for the project.

For example, if you need 20 pieces of 60′ rebar, you will need 1,200 linear feet of material. Rebar is typically sold in 20′, 30′, 40′, and 60′ lengths, but it is possible to order custom lengths as well.

You can use our rebar material calculator to find out how much rebar you need for your project. Alternatively, multiply the length of rebar by the quantity used to find the linear footage. Learn more about how to find linear footage.

Refer to the charts below for the dimensions for each size of rebar. Find the diameter and area of the rebar along with the weight per linear foot. To find the total weight, multiply the total length of rebar – total linear feet of material used – with the weight per linear foot if measured in feet, or weight per meter if measured in meters.

How to Find the Size and Weight of Rebar

Rebar, or reinforcing bar, is used in many masonry and concrete projects to reinforce slabs and structures. Because concrete has low compressive strength, rebar helps it bear loads without cracking.

Therefore, for most concrete projects, rebar is required to help the slab, footer, or foundation maintain its structural integrity. Rebar is available in standard sizes, making it easy to find the weight and dimensions of the rebar for your project.

The first step is to identify which size of rebar is being used on the project, for example, a #3 rebar. Most home and residential projects will use #3, #4 or #5 rebar, with #3 being used most commonly for patios and driveways, #4 for walls and columns, and #5 for footers and foundations.

The next step is to identify how much linear footage of rebar will be used. Linear footage is the total amount of length in 12″ increments needed for the project.

For example, if you need 20 pieces of 60′ rebar, you will need 1,200 linear feet of material. Rebar is typically sold in 20′, 30′, 40′, and 60′ lengths, but it is possible to order custom lengths as well.

You can use our rebar material calculator to find out how much rebar you need for your project. Alternatively, multiply the length of rebar by the quantity used to find the linear footage. Learn more about how to find linear footage.

Refer to the charts below for the dimensions for each size of rebar. Find the diameter and area of the rebar along with the weight per linear foot. To find the total weight, multiply the total length of rebar – total linear feet of material used – with the weight per linear foot if measured in feet, or weight per meter if measured in meters.

US Rebar Weight and Dimensions

US rebar sizes and dimensions

Imperial Bar Size “Soft” Metric Size Weight Nominal Diameter Nominal Area
lb/ft kg/m inch mm inch2 mm2
#2 #6 0.167 0.249 0.250 = 1/4“ 6.35 0.05 32
#3 #10 0.376 0.561 0.375 = 3/8“ 9.525 0.11 71
#4 #13 0.668 0.996 0.500 = 1/2“ 12.7 0.20 129
#5 #16 1.043 1.556 0.625 = 5/8“ 15.875 0.31 200
#6 #19 1.502 2.24 0.750 = 3/4“ 19.05 0.44 284
#7 #22 2.044 3.049 0.875 = 7/8“ 22.225 0.60 387
#8 #25 2.670 3.982 1.000 = 1″ 25.4 0.79 509
#9 #29 3.400 5.071 1.128 = 1 1/8“ 28.65 1.00 645
#10 #32 4.303 6.418 1.270 = 1 1/4“ 32.26 1.27 819
#11 #36 5.313 7.924 1.410 = 1 3/8“ 35.81 1.56 1006
#14 #43 7.650 11.41 1.693 = 1 3/4“ 43 2.25 1452
#18 #57 13.60 20.284 2.257 = 2 1/4“ 57.3 4.00 2581
Canadian Rebar Weight and Dimensions

Canadian rebar sizes and dimensions

Metric Bar Size Weight
kg/m		 Nominal Diameter
mm		 Nominal Area
mm2
10M 0.785 11.3 100
15M 1.570 16.0 200
20M 2.355 19.5 300
25M 3.925 25.2 500
30M 5.495 29.9 700
35M 7.850 35.7 1000
45M 11.775 43.7 1500
55M 19.625 56.4 2500
European Rebar Weight and Dimensions

European rebar sizes and dimensions

Metric Bar Size Weight
kg/m		 Nominal Diameter
mm		 Nominal Area
mm2
6,0 0.222 6 28.3
8,0 0.395 8 50.3
10,0 0.617 10 78.5
12,0 0.888 12 113
14,0 1.21 14 154
16,0 1.58 16 201
20,0 2.47 20 314
25,0 3.85 25 491
28,0 4.83 28 616
32,0 6.31 32 804
40,0 9.86 40 1257
50,0 15.4 50 1963
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Rebar Material Calculator

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Rebar Material Calculator

Calculate how much rebar you need to reinforce a concrete slab by entering the dimensions below, along with the desired spacing and the spacing between the edge and the rebar grid.

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Material Estimate

The number of bars needed and the length of each.

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{{ results.materialEstimate.length_bars_length }}
{{ results.materialEstimate.num_bars_length }}
{{ results.materialEstimate.length_bars_length }}
{{ results.materialEstimate.num_bars_width }}
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Equal Spacing

The spacing between each bar along the grid length or width.

Grid Size

The size of the rebar grid, accounting for the edge clearance.

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{{results.gridSize.width}}

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How to Estimate How Much Rebar You Need

When installing a concrete slab or structure, it is a good idea to add rebar, or reinforcing bar, to add strength to the concrete and prevent it from cracking down the road. Concrete is used frequently in construction, but it has low compressive and tensile strength on its own.

Using rebar as reinforcement adds considerable strength to concrete and reduces the overall slab thickness needed.[1] It also gives structural support and enables concrete to be used for things like foundations that must support heavy weight.

Calculating the amount of bar needed can be done in a few simple steps.

Step One: Figure Out the Grid Spacing

Rebar is often installed in a grid pattern, and to estimate the amount needed, it will be important to first identify the size and spacing that is appropriate for your project. There are three different sizes of rebar typically used for home construction projects. #3 is most commonly used for patios and driveways, #4 for columns and walls, and #5 for foundations and footers.

In addition, the spacing of the bars will also vary by the project. For flat slabs like driveways and patios, spacing is roughly 18″ to 24″. For walls, the rebar is typically spaced vertically at a minimum of every 36″ on center, coming to within 8″ of the top of the wall, and horizontally every 24″ minimum, within 12″ of the top and bottom of the wall.

Foundations must have rebar spaced no more than 18″ apart in order to meet building codes, but the exact placement can vary depending on the size and shape of the footer and the depth of the concrete. However, each project can vary in spacing and clearance, depending on things like weight, use, and even climate.

Different projects require different size rebar and will require the rebar to be spaced differently. Most projects require rebar to be laid in a grid pattern with bars running in opposite directions and overlapping.

The use of steel or fiber mesh can be used as an alternate form of reinforcement in some circumstances and is often used for thinner and smaller slab pours, including concrete countertops. Try our reinforcing mesh calculator to estimate.

Step Two: Estimate the Rebar Grid Clearance

Once you have identified the specs for your rebar, you’ll need to identify how much clearance or space is needed between the rebar grid and the edge of the slab. This is needed to determine both the lengths of the rebar and how many rows and columns are needed.

Clearance can vary by project and the direction of the rebar. For example, in a wall, you may need 8″ of clearance at the top but only 2″ on the sides.

Subtract the clearance from the length and width to find the dimensions of the grid. For example, if the slab is 10′ x 10′ and the clearance is 3″, the size of the rebar grid will be 9′ 6″ x 9′ 6″.

Step Two: Estimate the Rebar Grid Clearance

Once you have identified the specs for your rebar, you’ll need to identify how much clearance or space is needed between the rebar grid and the edge of the slab. This is needed to determine both the lengths of the rebar and how many rows and columns are needed.

Clearance can vary by project and the direction of the rebar. For example, in a wall, you may need 8″ of clearance at the top but only 2″ on the sides.

Subtract the clearance from the length and width to find the dimensions of the grid. For example, if the slab is 10′ x 10′ and the clearance is 3″, the size of the rebar grid will be 9′ 6″ x 9′ 6″.

Step Three: Estimate the Rows and Columns

Find the number of bars needed for each direction by dividing the width of the grid by the desired spacing. For example, if the width is 9′ 6″ and the spacing is 18″, the number of columns would be 8.

9′ 6″ = 114″
114″ / 18″ = 6.3
round 6.3 up to 7 to get complete coverage
add 1 additional bar for the last edge

The length of the bars will be the opposite dimension of the grid. Repeat this process to find the number of rows for the opposite direction.

Keep in mind that spacing is typically on center, meaning that you measure from the center of each piece of rebar, rather than from its edge when installing. In some vertical placements, you may also need to start the first row closer to the edge than the subsequent rows.

For example, you may start 12″ in, then go every 18″ to get the best placement. For vertical and structural applications such as walls and footers, always consult a structural engineer to get the exact placement and clearances recommended for that project.

Ordering the Right Amount of Rebar Material

Rebar is often available in 20′, 30′, 40′, and 60′ lengths. If your grid dimensions are larger than the lengths available, you will need to overlap the bars to get a long enough length.

If this is the case, you will need to order additional material to account for the overlap. Use our rebar weight and size calculator to find the total length of rebar needed for your project and estimate the total weight for purchasing. We recommend ordering 10% additional material to account for overlaps, cutoffs, and waste to prevent a shortage when installing.

Recommended Masonry Resources

Concrete Weight Calculator

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Concrete Weight Calculator

Find how much concrete weighs by entering the volume below. Use our concrete calculator to find the volume of concrete.

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How Much Does Concrete Weigh?

Concrete is a mixture of cement bonded with fine and coarse aggregates, including sand and crushed stone. This heavy material is used in many applications for building and construction.

A typical concrete mix weighs 150 lbs per cubic foot, 4,050 lbs per cubic yard, or 2,400 kg per cubic meter. The weight of concrete is determined by its density, which can vary based on the amount and type of aggregate, water, and air in the mix.

How much does a yard of concrete weigh?

The average yard of concrete weighs 4,050 lbs. However, this can vary a little depending on different factors, such as the amount and type of aggregate that are added to the mixture.

How to Find the Weight of Concrete

You can calculate the weight of concrete in a few easy steps. Since the weight is determined by the density and volume, the first step is to calculate the density, then calculate the weight.

Step One: Determine the Density of Concrete

Density is the measure of mass for a given volume and is defined by the formula:

density (ρ) = mass (m) ÷ volume (V)

The density of concrete is 3.15 g/cm3, while the density of aggregate will vary by the type of stone used. Most concrete will contain some amount of aggregate in the form of gravel or stone, which are added for strength. Some concrete mixtures use different levels and types of aggregate.

You will need to know the precise type of concrete and aggregate you are using for the most accurate weight. For instance, gravel has a much higher density than vermiculite. The density of a typical concrete mix is 2.4 g/cm3 or 150 lbs/ft3.

Different mixes of concrete will use more or less aggregate as well. For instance, the preferred concrete mix for a countertop will have less aggregate than the mix for a driveway or footing because the countertop does not need to be as strong, which will affect the density and, thus, the weight of the concrete.

Density of concrete in different units of measure

Volume Weight
1 in3 1.39 oz
1 ft3 150 lb
1 yd3 4050 lb
1 m3 2400 kg
Step Two: Determine the Weight of Concrete

The density of concrete is determined by mass and volume. Since the density is known, the formula for mass can be changed by multiplying the density by the volume.

mass (m) = volume (V) × density (ρ)

For example, let’s find the weight of 25 cubic feet of concrete.

weight = 25 cu ft × 150 lb/cu ft
weight = 3,750 lbs

Tip: Use our cubic feet calculator to find the volume in feet.

For example, let’s find the weight of 3.5 cubic yards of concrete.

weight = 3.5 cu yd × 4,050 lb/cu yd
weight = 14,175 lbs

Tip: Use our cubic yards calculator to find the volume in yards.

You can use this method to calculate the weight of other materials or substances, such as the weight of water or even milk.

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Concrete Steps Calculator

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Concrete Steps Calculator

Find the amount of concrete needed to pour steps. The calculator also supports a platform at the top of the steps, leave this empty to use the run dimension for the top step.

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How to Estimate Concrete for Steps

Concrete is a popular material for both short and long runs of steps. It’s durable, long-lasting, and fairly easy to work with. Estimating the concrete needed to pour steps may seem daunting, but because it’s a simple shape to estimate, it can be done in a few simple steps.

Divide the Steps into Rectangles

The first step to estimate the volume of a set of steps is to divide the steps into smaller rectangles. Finding the volume of a rectangular prism is much easier than finding the volume of a complex shape. Think about each step as a rectangle from the top of the step to the ground and the platform (the largest step at the top) as a single rectangle.

You’ll find the volume of each one of these separately, then add them together to find the total volume for the concrete pour.

Find the dimensions of each rectangle and measure the volume for them separately. Use our concrete calculator to assist in this process.

The dimensions of each rectangle will be the run (or depth) by the vertical rise from the ground for that step, multiplied by its width.

For example, if the steps you are pouring are 48″ wide, then the width of each step and the platform will be 48″.

If the depth of each stair tread is 10″ and the depth of the platform itself is 24″, you will then need the height of each step.

The first step’s volume may be:

48″ × 10″ × 8″ = 3,840 cu in

The second step may be:

48″ × 10″ × 16″ = 7,680 cu in

The dimensions of the platform can be found by multiplying the platform depth by the height of the platform from the ground by the width of the total stairs.

Find the Volume of Each Rectangle Section

The dimensions of each rectangle can be used to find the volume of each using the formula for volume, length × width × height. Simply multiply the step width by the depth and height for each rectangle section.The dimensions of each rectangle can be used to find the volume of each using the formula for volume, length × width × height. Simply multiply the step width by the depth and height for each rectangle section.

Find the Total Step Volume

The final step is to add the volumes of each step section together to get the total volume of the steps. If your measurements are in inches, then. your total volume will be in cubic inches.

Because most concrete is poured in cubic yards, you will need to convert your final measurements.

For example, if you have been measuring the volume for a set of 5 steps with a width of 48″, tread depths of 10″, a platform of 24″ in depth, and a total height of 40″, your final stairs would have a volume of 84,480 cubic inches.

To get cubic yards, you would divide your total cubic inches by 46,660. In this case, you would need 1.81 cubic yards of concrete to complete the pour.

Adding 10% for waste and potential voids gets 1.99 cubic yards, which would most likely be rounded to 2 full yards.

Our concrete step volume calculator can help find how much concrete you need to pour your steps, but you can also hire a professional contractor to measure and pour your steps.

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Concrete Reinforcing Mesh Calculator

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Concrete Reinforcing Mesh Calculator

Enter the dimensions of the slab and the size mesh used to calculate the amount of concrete reinforcement needed.

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How to Estimate Concrete Reinforcement Mesh

Mesh is a popular material used to reinforce concrete slabs and pours. It may be used in place of rebar for thinner slabs or in addition to rebar for thicker pours.

Mesh may be wire or made of fiber. Metal mesh is laid before the concrete is poured, then lifted to the center, while fiber mesh is placed in the concrete evenly as it is poured.

Both these materials are common for projects like sidewalks and patios that may not hold heavy loads. The amount of mesh reinforcement needed for a project can be calculated in a few easy steps.

Step One: Calculate the Slab Area

The first step to estimating reinforcement is to find the size of the concrete slab that will be poured. If you already know this figure, then you can skip ahead to the second step.

The area of the pour can be found by multiplying the length in feet by the width in feet. The result is the square footage of the slab.

Here’s the formula to find area:

area = length × width

For shapes other than a rectangle, you’ll need the appropriate formula to calculate the area, or you can use a square footage calculator.

Step Two: Calculate Mesh Coverage

The second step is to find the coverage of the mesh roll or sheets that will be used for the project. Sometimes the coverage in square feet is provided by the manufacturer, but if not, it can be found using the area formula above.

Step Three: Divide Slab Area by Reinforcement Area

The final step in estimating the number of rolls or sheets of mesh reinforcement is to divide the square footage of the slab by the square footage of the reinforcing mesh. This is the formula:

mesh needed = slab area ÷ mesh area

For example, let’s find the number of 5′ x 50′ rolls of mesh required to reinforce a slab that is 25′ by 25′.

First, find the area of the slab.

area = 25′ × 25′
area = 625 sq ft

Next, find the coverage of the roll.

coverage = 5′ × 50′
coverage = 250 sq ft

Finally, divide the slab area by the coverage.

rolls needed = 625 sq ft ÷ 250 sq ft
rolls needed = 2.5

Thus 2 ½ 5′ x 50′ rolls will be needed to reinforce a 25′ x 25′ slab.

How to Account for Lapping

One thing to consider when calculating reinforcing mesh material is to account for overlap when using wire mesh. Lapping is required with wire mesh to improve the strength around the edge of the mesh and resist cracking.

Fiber mesh does not require any overlap because of the way that it is distributed through the concrete during the pour.

Wire mesh should overlap at all edges and ends by a minimum of 2 ½”. Larger overlaps are fine and sometimes necessary if the material is having difficulty laying flat.

To account for lapping, calculate the overlap as a percentage of additional material needed. The formula to find the overlap percentage is:

lapping percentage = overlap ÷ reinforcement width

For instance, let’s find the lapping percentage for a 6″ lap when using a 5′ wide roll of mesh. Note that 5′ is equal to 60″, which is the figure used in the formula below.

lapping percentage = 6″ ÷ 60″
lapping percentage = .10

Thus, a 6″ lap will require 10% additional material because .10 is equal to 10%.

Don’t forget to try our concrete calculator to determine the right amount of concrete needed for your next pour.

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Concrete Mix Calculator

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Concrete Mix Calculator

Use our concrete mix calculator to find how much Portland cement, sand, and gravel you need for your mix.

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How to Calculate a Concrete Mix

If you’re planning your next concrete project, then you need to consider whether to buy pre-mixed concrete, have a load of ready-mix delivered, or mix your own. If you choose to mix your own, then you can follow standard ratios to ensure you get a mix that’s durable and strong.

The ratios of the basic ingredients for concrete can change with the application. Rougher, larger aggregate may be added for some projects that need extra strength, while more sand and finer aggregates may be needed for a countertop.

A good concrete mix is composed of four basic ingredients:

  • Portland cement
  • sand
  • gravel or aggregate
  • water

The proportions of each ingredient in the mix will determine how strong the resulting concrete is – this is referred to as compressive strength. These ratios are called the mix ratio.

The mix ratio for a standard M5 concrete is 1:5:10, and when mixed and poured correctly will yield concrete with a 725 psi compressive strength.

This is a formula you would follow for areas that need good compressive strength like a patio. However, for supports or driveways that will handle heavy trucks, you may need a formula that will yield concrete with a higher psi.

The parts of the ratio refer to the amount of Portland cement, sand, and aggregate needed, in order. So for this ratio, for every 1 part Portland cement, you’ll need 5 parts sand and 10 parts aggregate or gravel.

There are also additives that can be added to the mix to increase working time, reduce curing time, add color, and more.

Steps to Estimate Cement, Sand, and Gravel

You can calculate the amount of Portland cement, sand, and gravel needed for a concrete mix by following a few simple steps.

Step One: Calculate the Dry Volume

One important consideration when estimating a concrete mix is the difference between the wet and dry volume. When you measure a space and determine its volume in cubic yards, this is a wet volume, or rather, the amount of wet concrete needed to fill it in.

The dry volume of the mix is the volume of the dry ingredients before adding water. The dry mix actually consumes more volume before adding water due to all of the air – 54% more, in fact!

When adding water, the mix will settle and shrink, taking less space overall. Because the liquid concrete is what you will be working with, you will need to adjust for this before mixing.

So, the first step to estimating materials is to calculate the dry volume. You can do that by multiplying the wet volume required by 54%.

dry volume = wet volume × 1.54
Step Two: Calculate the Percentages of Each Part

The second step is to calculate the percentage of each part in the mix. Start by adding up each part in the ratio to find the total number of parts.

For instance, for the M5 1:5:10 mix ratio, add up the cement, sand, and gravel parts like this:

1:5:10 mix -> 1 + 5 + 10 = 16 parts

So, in the M5 mix, there are 16 total parts.

Now, for each component in the mix, divide the number of parts by the total number of parts to find its percentage of the dry volume.

1 part cement -> 1/16 = 0.0625
5 parts sand -> 5/16 = 0.3125
10 parts gravel -> 10/16 = 0.625

So, the M5 mix is composed of 6.25% cement, 31.25% sand, and 62.5% gravel.

Step Three: Calculate the Volume of Each Component

Now, it’s time to calculate the volume of each component in the mix. Do this by multiplying the percentage of each one by the dry volume required.

Continuing the example using the M5 mix, multiply the percentage of cement, sand, and gravel by the dry volume required to find the volume of each needed for the mix.

For example, let’s calculate the amount of cement, sand, and gravel for the M5 mix to fill one cubic yard of space.

Start by calculating the dry volume of the mix.

dry volume = 1.0 × 1.54 = 1.54 cu yds

dry volume = 1.0 × 1.54 = 1.54 cu yds

Recall the percentages for this mix are:

1 part cement -> 1/16 = 0.0625
5 parts sand -> 5/16 = 0.3125
10 parts gravel -> 10/16 = 0.625

Now, multiply each of these percentages by the dry volume to find the volume of each one required for the mix.

cement -> 0.0625 × 1.54 = 0.09625 cu yds
5 parts sand -> 0.3125 = 0.48125 cu yds
10 parts gravel -> 0.625 × 1.54 = 0.9625 cu yds

This is the same process used to estimate materials for a mortar or grout mix.

Standard Concrete Mix Ratios

The table below shows the standard mix ratios for various grades of concrete.

Concrete Grade Mix Ratio Compressive Strength
M5 1 : 5 : 10 5 MPa (725 psi)
M7.5 1 : 4 : 8 7.5 MPa (1087 psi)
M10 1 : 3 : 6 10 MPa (1450 psi)
M15 1 : 2 : 4 15 MPa (2175 psi)
M20 1 : 1.5 : 3 20 MPa (2900 psi)
M25 1 : 1 : 2 25 MPa (3625 psi)

Table showing the mix ratios of cement, sand, and aggregate for standard grades of concrete

Water to Cement Ratio

The amount of water you add to your concrete mix is also important. Having a low water ratio can actually improve the strength of concrete, but can make it very hard to work with, which may impact final quality.

Likewise, adding too much water will end up making the final concrete too brittle. Therefore, you need to get the right mix of water to concrete.
Below is the maximum amount of water to concrete ratio recommended for each type.

Concrete Mix Max Water Cement Ratio
M5 .60
M7.5 .60
M10 .60
M15 .50
M20 .45
M25 .40

Table showing the ratio of water to the mix of concrete

Notice that as compressive strength goes up, the amount of water required goes down. To determine how much water you need for your project, you will use the following formula:

water/cement ratio × weight of the cement needed

One cubic yard of dry mix weighs roughly 3,600 pounds. Keep in mind that as you adjust the ratios, the weight may vary.

To find the water needed for 1 cubic yard of M5 dry mix, you would use this formula:

3,600 × .60 = 2,160 pounds of water

Each gallon of water weighs 8.34 lbs, so one cubic yard of M5 dry mix would require 259 gallons of water to complete.

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Concrete Block Fill Calculator

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Concrete Block Fill Calculator

Find the core fill volume for a concrete block wall and estimate how much grout is required to fill the block using the width and height of a wall or given a number of CMUs to fill.

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How to Find Concrete Block Core Fill Volume

Concrete blocks used for construction, also known as concrete masonry units (CMUs) or cinder blocks, typically have one or two holes or voids known as cells to reduce the weight of the block. These cells are filled with concrete or grout during the installation process to strengthen and reinforce the wall. To estimate how much concrete or grout is needed to fill those cells, you need to find the volume necessary to fill each block, then multiply that by the total number of blocks in the wall.

Step 1: Find the Volume of Each Block Void

To get the volume of each block, begin by getting its total size in inches. The standard size for a CMU is 8″ x 8″ x 16″, but there are many variations.

Each CMU is made up of two “shells” along the front and back and two to three “webs”, which run from the front to the back of the block. Measure the thickness of each one, then subtract the width of the shells from the width and the width of the webs from the length of each block.

You will also need the number of cells, with two being standard. You will divide the total length by the number of cells. In a block that measures 8″ x 8″ x 16″, this will look like:

Width: 8″ – 1″ (shell) – 1″ (shell) = 6″
Length: 16″ – 1″ (web) – 1″ (web) – 1″ (web) ÷ 2 cells = 6.5″
Height: 8″

Multiply the new width and length by the height of each block to get the cubic inches for that block:

6″ × 6.5″ × 8″ = 312 cu in/block

Keep in mind that CMU measurements are nominal, meaning that they are often slightly smaller than their given measurements to account for the mortar between them. You may also have a block with custom web and shell measurements, which can change the total volume.

To get the most accurate volumes, always measure each area on the block yourself, and use those measurements when doing the calculation. Use our volume calculator to simplify this process.

Step 2: Find the Number of Blocks in the Wall

The next step is to find the number of blocks in the wall. This can be done by counting the number of blocks in the wall, or by getting the square footage of the wall and of the block you want to use and dividing the total square footage of the wall by the square footage of the block.

For an 8 x 16 block, this is 0.89 sq ft. Or, use our concrete block calculator to find how many blocks are in your wall.

Step 3: Find the Total Concrete Block Fill Volume

Multiply the cubic inches of volume for one block by the total number of blocks in the wall to get the total volume in cubic inches. Divide the final number by 46,656 to find the volume in cubic yards. A conversion calculator can make this easy.

Fill Volume for Various Block Wall Thicknesses

Below are the average fill volumes needed for a 100-square-foot wall based on the thickness of the wall. Keep in mind that these volumes can change if you are using a block with different web or shell measurements or if you are using a block that is not 8″ x 16″ in face measurements.

Block Wall Thickness Blocks Filled per Cubic Yard Concrete/Grout per 100 Block Concrete/Grout per 100 Square Feet Wall Area
6″ 120 .83 yd3 .93 yd3
8″ 100 1.0 yd3 1.12 yd3
10″ 80 1.23 yd3 1.3 yd3
12″ 65 1.54 yd3 1.73 yd3

Approximate grout fill volume and coverage for a concrete block wall.

Frequently Asked Questions

In most cases cinder blocks or CMUs do not need to be filled. Adding fill is a process referred to as grouting, and can add considerable strength to a block wall, reducing the likelihood of cracking. However, some experts argue that in cold or freezing climates, fill material can expand or contract causing the blocks to crack over time.

The most commonly used materials to fill the cells or voids in concrete blocks is mortar, concrete, sand, and gravel to add strength. These don’t offer much insulation value, but you can fill the block using insulation.

You will need one cubic yard of fill for every 100 blocks for an 8″ thick wall.

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Concrete Block Calculator

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Concrete Block Calculator

Calculate how many concrete blocks and bags of mortar are needed for your project by entering your wall dimensions and block size. Add the block price to get an estimated material price estimate.

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How Many Concrete Blocks Do You Need?

Concrete blocks are an affordable building material that can be used for many construction projects and are suited very well for construction walls for foundations or utility buildings.

Concrete blocks technically fall into two categories; solid blocks, which are commonly used for things like retaining walls, and CMUs, or concrete masonry units.

CMUs are hollow blocks that need to be filled with concrete during installation. Because the most common type of CMU is made of a mixture of cement and coal ash, these units are also frequently called cinder blocks.[1]

CMUs are available in many sizes, but the most common is 8″ deep x 8″ high x 16″ long.

A concrete block wall typically requires 1 1/8 blocks per square foot.

To determine how many blocks you’ll need for a project, enter the dimensions of your wall project into the calculator above, and it will figure out how many blocks you need. Alternatively, you can also follow the instructions below to calculate them manually.

Note: Retaining walls are often constructed from a different material than CMUs. If you’re building a retaining wall, then try our retaining wall calculator.

How to Calculate Concrete Blocks

There are several formulas to figure out how many concrete blocks are necessary for a wall project. Start by measuring the wall’s width and height in feet.

Step One: Find Wall Square Footage

Once you have the wall measurements, calculate the square footage of the wall by multiplying the width times the height.

wall sq ft = width × height
Step Two: Find Block Square Footage

Now you need to figure out the square footage of the block you are using. To do this, multiply the height and length of the block and divide by 144 – the number of square inches in a foot. The standard block size is 8″ high x 16″ long and has a square footage of 0.89.

block sq ft =
8 × 16
144
= 0.89 sq. ft.

Different size blocks will have different square footages; apply the formula above to find the solution. Check out our square footage calculator to determine the square footage of your block.

Step Three: Calculate Blocks

After you have found the square footage of both your wall and your block, determining the number of blocks you need is as simple as dividing the wall square footage by the block square footage.

blocks =
wall sq ft
block sq ft
blocks =
wall sq ft
0.89

We recommend adding 5%-10% additional blocks to account for broken blocks or blocks that need to be cut for the edges.

Our calculator above may indicate a different quantity of blocks needed since it uses a more precise formula, accounting for partial blocks and cutoffs automatically.

How to Estimate Mortar for a Block Wall

Calculating the amount of mortar needed for the joints in a concrete block wall will vary depending on the mortar mix you use. Mortar is a mixture of cement and sand, usually with other additives.

If you are planning on mixing your mortar yourself, you will need a yield of 1:3 cement to sand mixture. On average, it takes about three bags of cement for every 100 blocks.

Divide the number of blocks being installed by 33.3 to calculate how many bags are needed. Once you have the number of bags, you will need one cubic yard of sand for every seven bags of cement.

You can also purchase pre-mixed bags of mortar, which can come in different formulations. Each formulation and brand may vary in how many blocks the mortar will bond.

Try our mortar calculator to calculate how many bags are needed.

How to Estimate Grout or Concrete Fill

CMUs are hollow and designed to be filled with concrete during installation. Estimating the concrete needed to fill the cells in concrete block involves getting more measurements from the blocks.

When looking at a block from the top down, the areas that run front to back on the block are called “webs”, while the areas that run side to side are called the “shell”. To calculate the fill volume, you will need the number of webs, their thickness, and the thickness of the shell.

Typical measurements for webs and shells may be around 1″ or 1.25″ depending on the size of the block.

The fastest way to get an accurate volume of the cells in the CMUs is to take the length and width of the block and subtract the shell and web measurements. For a block is 8″ x 8″ x 16″, this would look like:

Width: 8″ – 1″ (shell) – 1″ (shell) = 6″
Length: 16″ – 1″ (web) – 1″ (web) – 1″ (web) ÷ 2 cells = 6.5″
Height: 8″

The volume of the core would therefore be:

6″ × 6.5″ × 8″ = 312 cu in/block

Multiply this by the total number of blocks, and divide by 46,660 to get the total number of cubic yards needed.

Use our block fill calculator to estimate the fill volume.

Tools Needed to Install a Concrete Block Wall

If you’re installing a concrete block wall, you will need several tools to correctly do the job. Here is a small list of tools that are necessary to build a wall.

  • Brick Trowel: This is used to lay an even bed of mortar when setting the blocks.
  • Mason Line: Use mason line to ensure the wall is straight and level and the blocks are set at an even height.
  • Level: Make sure you have a level on hand to verify that each block is straight and level with adjacent blocks.
  • Jointer: Use the jointer to remove excess mortar between the blocks.
  • Tape Measure: Use a tape measure to lay things out.
  • Mixing Tub: Mix mortar in a mixing tub to keep your wheelbarrow clean.

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Standard Concrete Block Sizes

You’ll need to know the size of the concrete block you’ll be using to determine how many blocks you need for your project. The most common sizes are 8″ high by 8″ wide and 8″ high by 16″ wide in varying thicknesses.

The block’s thickness is not critical to finding how many blocks you need, but it is essential when estimating how much mortar and other masonry material you need. The common thicknesses are 4″, 6″, 8″, 10″, 12″, and 14″.

Refer to the tables below for standard block sizes, including the nominal dimensions. The nominal size is the block’s actual size, while the size includes a 3/8″ mortar joint and is the size that should be used when estimating material.

The standard mortar joint should be 3/8″ thick for your wall.

2″ and 3″ CMU Block Dimensions

Chart showing the dimensions of standard 2″ and 3″ blocks and the number of blocks needed per 100 sq ft of wall

Size D x H x L Nominal D x H x L Blocks per 100 ft2
2″ x 8″ x 16″ 1 5⁄8” x 7 5⁄8” x 15 5⁄8“ 113
3″ x 8″ x 16″ 2 5⁄8” x 7 5⁄8” x 15 5⁄8“ 113
4″ CMU Block Dimensions

Chart showing the dimensions of standard 4″ blocks and the number of blocks needed per 100 sq ft of wall

Size D x H x L Nominal D x H x L Blocks per 100 ft2
4″ x 8″ x 8″ 3 5⁄8” x 7 5⁄8” x 7 5⁄8“ 226
4″ x 8″ x 16″ 3 5⁄8” x 7 5⁄8” x 15 5⁄8“ 113
6″ CMU Block Dimensions

Chart showing the dimensions of standard 6″ blocks and the number of blocks needed per 100 sq ft of wall

Size D x H x L Nominal D x H x L Blocks per 100 ft2
6″ x 8″ x 8″ 5 5⁄8” x 7 5⁄8” x 7 5⁄8“ 226
6″ x 8″ x 16″ 5 5⁄8” x 7 5⁄8” x 15 5⁄8“ 113
8″ CMU Block Dimensions

Chart showing the dimensions of standard 8″ blocks and the number of blocks needed per 100 sq ft of wall

Size D x H x L Nominal D x H x L Blocks per 100 ft2
8″ x 8″ x 8″ 7 5⁄8” x 7 5⁄8” x 7 5⁄8“ 226
8″ x 8″ x 16″ 7 5⁄8” x 7 5⁄8” x 15 5⁄8“ 113
10″ CMU Block Dimensions
Chart showing the dimensions of standard 10″ blocks and the number of blocks needed per 100 sq ft of wall
Size D x H x L Nominal D x H x L Blocks per 100 ft2
10″ x 8″ x 8″ 9 5⁄8” x 7 5⁄8” x 7 5⁄8“ 226
10″ x 8″ x 16″ 9 5⁄8” x 7 5⁄8” x 15 5⁄8“ 113
12″ CMU Block Dimensions

Chart showing the dimensions of standard 12″ blocks and the number of blocks needed per 100 sq ft of wall

Size D x H x L Nominal D x H x L Blocks per 100 ft2
12″ x 8″ x 8″ 11 5⁄8” x 7 5⁄8” x 7 5⁄8“ 226
12″ x 8″ x 16″ 11 5⁄8” x 7 5⁄8” x 15 5⁄8“ 113
14″ CMU Block Dimensions
Chart showing the dimensions of standard 14″ blocks and the number of blocks needed per 100 sq ft of wall
Size D x H x L Nominal D x H x L Blocks per 100 ft2
14″ x 8″ x 8″ 13 5⁄8” x 7 5⁄8” x 7 5⁄8“ 226
14″ x 8″ x 16″ 13 5⁄8” x 7 5⁄8” x 15 5⁄8“ 113

How Much Does a Block Wall Cost?

A wall typically costs $10 – $15 to install; learn more about a wall project’s cost factors. We suggest getting several professional estimates to get the best labor cost and find the right company for your project.

Check out our concrete calculator to help with your other concrete projects.

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