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Concrete Volume Calculator

Calculate cubic yards and cubic feet of concrete needed for a slab, footing, or pad — given length, width, and depth.

Inputs

Thickness of the slab in inches.

Standard 5-10% buffer for spillage and uneven sub-grade.

Result

Concrete needed
1.36 yd³
36.7 cubic feet (with 10% waste).
  • Pure volume1.235 yd³ (33.3 ft³)
  • Waste buffer10%
  • Order quantity1.36 yd³

Step-by-step

  1. Convert depth to feet: 4 in ÷ 12 = 0.333 ft.
  2. Volume = L × W × D = 10 × 10 × 0.333 = 33.33 ft³.
  3. Cubic yards = 33.33 ÷ 27 = 1.235 yd³.
  4. Add 10% waste: 1.235 × 1.10 = 1.36 yd³.

How to use this calculator

  • Enter the length and width of the slab in feet.
  • Enter the depth (slab thickness) in inches — most patios are 4 in, driveways 4-6 in, footings 8-12 in.
  • Adjust the waste factor; 10% is a safe default for residential pours.

About this calculator

Concrete is sold and ordered by the cubic yard. To figure out how much you need, multiply length × width × depth — making sure all three are in the same units — then divide by 27 to convert cubic feet to cubic yards. Adding a small waste factor (5-10% is standard) covers spillage, uneven sub-grades, and the inevitable last-minute "we should pour the front step too".

Frequently asked

Patios and walkways: 4 inches. Driveways for cars: 4 inches. Driveways for trucks/RVs: 5-6 inches. Footings and structural slabs: 8-12 inches. Always check local code for footings.

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