Concrete Volume Calculator
Cubic yards of concrete for a rectangular slab/footing OR a cylindrical column/sonotube — with waste factor.
Result
Concrete needed
1.36 yd³
36.67 cubic feet (with 10% waste). Rectangular slab.
- Pour shapeRectangular (10×10 ft)
- Pure volume1.235 yd³ (33.33 ft³)
- Waste buffer10%
- Order quantity1.36 yd³
- 60-lb bags (≈ 0.45 ft³ each)82 bags
- 80-lb bags (≈ 0.60 ft³ each)62 bags
Step-by-step
- Convert depth to feet: 4 in ÷ 12 = 0.333 ft.
- Volume = L × W × D = 10 × 10 × 0.333 = 33.33 ft³.
- Cubic yards = 33.33 ÷ 27 = 1.235 yd³.
- 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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