Concrete Slab Calculator
Estimate concrete for a slab — patio, garage, or shed floor. Enter length, width, and thickness to get cubic yards and 40/60/80 lb bag counts, with a cost estimate.
How thick should a concrete slab be?
| Use | Typical thickness |
|---|---|
| Patio / walkway | 4 in |
| Shed floor | 4 in |
| Driveway | 4–5 in |
| Garage floor | 5–6 in |
Common slab sizes (at 4 in)
| Slab | Concrete |
|---|---|
| 8 × 8 ft | ~0.79 cu yd |
| 10 × 10 ft | ~1.23 cu yd |
| 12 × 12 ft | ~1.78 cu yd |
| 24 × 24 ft (garage) | ~7.11 cu yd |
Related calculators
Concrete calculator (all shapes) · Gravel base calculator
FAQ
How thick should a concrete slab be?
4 in for patios/walkways; 5–6 in for driveways and garage floors.
How much concrete for a 12×12 slab?
About 1.78 cu yd (48 cu ft) at 4 inches. Add 5–10% for waste.