How to Calculate Concrete Yards
Multiply length by width by depth in feet to get cubic feet, then divide by 27 to get cubic yards. Add a waste factor before ordering.
Concrete yard formula
- Depth in feet = depth in inches / 12
- Cubic feet = length x width x depth in feet
- Cubic yards = cubic feet / 27
- Order quantity = cubic yards x (1 + waste percentage)
Example: 10x10 slab
A 10 ft by 10 ft slab that is 4 inches thick is 100 sq ft x 0.333 ft, or about 33.3 cubic feet. Divide by 27 to get about 1.23 cubic yards before waste.
Use the calculator
For a project-specific estimate, enter your measurements in the Concrete Calculator.
Frequently asked questions
Why divide by 27?
One cubic yard contains 27 cubic feet because 3 x 3 x 3 = 27.
Should concrete be rounded up?
Yes. Running short during a pour is costly, so include waste and round to supplier ordering units.