Free tool · Volume
Concrete Calculator
Enter the size of the slab, footing, wall or column and get the volume in cubic yards. Add a waste allowance, and an optional price per yard if you want a rough cost.
Lengths are in feet and thicknesses are in inches, the way plans are read. The numbers stay in your browser: nothing is saved or sent anywhere.
Net volume
— cubic yards
— cubic feet
With 5% waste
— cubic yards
Enter the sizes above
The formulas
Slab: length × width × thickness (in feet) gives cubic feet. Divide by 27 for cubic yards.
Footing: total run length × width × depth, with width and depth converted from inches to feet.
Wall: length × height × thickness.
Round column: π × (diameter ÷ 2)² × height, again with the diameter in feet, times the number of columns.
A worked example
A 20 ft × 20 ft slab, 4 inches thick, is 133.3 cubic feet, or 4.94 cubic yards. With a 5 percent waste allowance that becomes 5.19 cubic yards.
A footing 100 ft long, 24 inches wide and 12 inches deep is 200 cubic feet, or 7.41 cubic yards. A 30 ft long, 8 ft high, 8 inch thick wall is 160 cubic feet, or 5.93 cubic yards.
About the waste allowance
Forms are rarely perfect, subgrades are rarely flat, and some concrete stays in the truck and the pump. Many estimators add an allowance for this. The right figure depends on your site, so the box is yours to change. Ready-mix plants usually sell by the yard, and many charge extra for a short load, so check your supplier’s minimum before you round down.
What this does not include
The calculator gives concrete volume only. It does not cover reinforcing steel, forming, finishing, curing, pump or placement labor, or the subgrade work. Those are separate lines in a real bid, and adding them correctly is what a takeoff is for.
FAQ
How many cubic feet are in a cubic yard?
27. A cubic yard is 3 ft × 3 ft × 3 ft.
How do I convert inches to feet for thickness?
Divide by 12. A 4 inch slab is 0.333 ft thick. The calculator does this for you.
Does this work for a thickened-edge slab or a stepped footing?
Calculate each section on its own and add the results. Use the “how many of these” box when the same piece repeats.
Is anything I type saved?
No. The calculation runs in your browser and nothing is stored or sent to us.
Doing a full concrete takeoff? PoPs Estimating measures it from your plans and keeps the quantities tied to the bid.
Questions?
Ask us anything about PoPs Suite, pricing, or running a construction company. A real person answers, usually within a business day.