Your dimensions · visible math
Concrete Volume Calculator
Estimate rectangular concrete volume from measured length, width and a thickness supplied for your project. Choose each unit separately, then add your own allowance and optional order rounding.
No thickness is recommended here. Ask the responsible contractor or designer for the actual section before using this worksheet.
Your worksheet
Free to use. Inputs stay in this page and reset on reload. Print or download what you want to keep. Nothing is sent to the operator.
Use the worksheet above. With JavaScript off, use the formula below and your browser’s print menu.
Formula: cubic yards = length in feet × width in feet × thickness in feet ÷ 27
There are 27 cubic feet in one cubic yard. Divide an inch measurement by 12 to convert it to feet. Divide meters by 0.3048, or centimeters by 30.48. Convert all three measurements before multiplying; square feet and cubic feet measure different things.
A worked volume example
For arithmetic only, suppose the supplied dimensions are 12 feet long, 9 feet wide and 4 inches thick. The thickness is 4 ÷ 12 feet. Volume = 12 × 9 × (4 ÷ 12) = 36 cubic feet. Then 36 ÷ 27 = 1.333333… cubic yards. This example is not a recommended slab design.
If you choose a 10% allowance, multiply by 1.10: the result is 1.466667 cubic yards when displayed to six decimals. If you then choose to round up by 0.25 cubic yard, the worksheet shows 1.5 cubic yards. No allowance is added when the allowance box is blank. The supplier may use different order increments.
Check what the rectangle leaves out
Measure thickened edges, footings, steps or different depths as separate sections using their supplied dimensions. Do not count an opening twice. This worksheet does not calculate excavation, base material, reinforcing steel or delivery charges. Ask the contractor to verify measurements and the complete order.
Use the slab planning guide for scope questions and the cost calculator for your own square-foot rate. A cubic-yard quantity is not a square-foot installation price.
TradeLeo is a connection service, not a contractor. See the cost guide and operator details. You may separately request contractor contact after using the result; no request is needed to print or download it.
Before you decide
Good questions to ask
Where does the slab thickness come from?
Use the thickness supplied for your project by its responsible contractor or designer. The example is arithmetic only. This calculator does not recommend a thickness, reinforcement, mix or footing design.
Is the rounded quantity an order?
No. It is your selected rounding applied to your dimensions and allowance. Confirm actual measurements, supplier increments, access and the contractor’s order before buying. Irregular shapes or thickened edges need separate measurements.