Concrete Calculator
Concrete for a slab: cubic yards to order, or how many 80 lb and 60 lb bags to buy.
- Volume (cubic feet)33.3
- Volume (cubic yards)1.23
- 80 lb bags (≈0.6 cu ft each)56
- 60 lb bags (≈0.45 cu ft each)75
Inputs used
- Length10 ft
- Width10 ft
- Thickness4 in
About this calculator
A slab's volume is length × width × thickness — with thickness converted from inches to feet first. A 10 × 10 ft patio at 4 inches thick needs 10 × 10 × ⅓ ≈ 33.3 cubic feet, which is about 1.23 cubic yards (there are 27 cubic feet in a cubic yard).
Ready-mix trucks sell by the cubic yard; for small jobs, bagged mix works: an 80 lb bag yields about 0.6 cubic feet and a 60 lb bag about 0.45. The bag counts below round up, but order roughly 10% extra on top — uneven ground and spillage always eat some, and running short mid-pour is the one mistake you can't fix later.
Standard slab thicknesses: 4 inches for patios and walkways, 5–6 inches for driveways.
Results are informational only — not financial, medical or legal advice.