Calculate the Volume of Concrete

Concrete Volume Formula

The concrete volume formula is the same regardless of what you're building — you're always calculating the three-dimensional space the concrete will fill:

Volume (ft³) = Length (ft) × Width (ft) × Depth (ft)

The key is ensuring all dimensions are in the same unit. Since thickness is usually measured in inches, you must convert to feet before multiplying: divide inches by 12. Then divide cubic feet by 27 to get cubic yards (since 1 yd³ = 27 ft³).

Unit Conversion Reference

Volume of Common Shapes

Rectangle: L × W × D (all in same unit)

Circle: π × r² × D (where r = radius, D = depth/thickness)

Cylinder (post hole): π × r² × h (where h = depth)

Frequently Asked Questions

• How do you calculate the volume of concrete?
  Multiply Length (ft) × Width (ft) × Thickness (convert inches to feet by ÷12). That gives cubic feet. Divide by 27 for cubic yards. Add 10% waste. Example: 10×10 slab at 4" = 10 × 10 × 0.333 = 33.3 ft³ ÷ 27 = 1.23 yd³ × 1.10 = 1.35 yd³.
• How many cubic feet in a cubic yard of concrete?
  Exactly 27 cubic feet per cubic yard (3 ft × 3 ft × 3 ft = 27 ft³). This is the fundamental conversion for all concrete volume math.
• How much does one cubic yard of concrete weigh?
  A cubic yard of standard concrete weighs approximately 3,900–4,050 pounds (about 2 tons). This is why concrete truck weight limits matter — a full 10-yard load weighs 20+ tons.