10×10 slab: concrete by thickness
| Thickness | Cu ft | Cu yd | 80 lb bags | 60 lb bags |
|---|---|---|---|---|
| 3.5″ | 29.17 | 1.08 | 49 | 65 |
| 4″ | 33.33 | 1.23 | 56 | 75 |
| 5″ | 41.67 | 1.54 | 70 | 93 |
| 6″ | 50.00 | 1.85 | 84 | 112 |
No waste included in the table.
Worked example
10 ft × 10 ft = 100 sq ft. At 4 inches: 100 × 4 ÷ 12 = 33.33 cu ft, or 1.23 cubic yards. With 10% extra that is 1.36 yd³, or 62 bags of 80 lb mix.
At over 1 cubic yard, compare the cost and labor of bags against a ready-mix delivery.
Assumes standard concrete mix bag yields: 80 lb ≈ 0.60 cu ft, 60 lb ≈ 0.45 cu ft. Check the yield on your bag. 1 cubic yard = 27 cubic feet.
Frequently asked questions
How many bags of concrete for a 10×10 slab?
56 × 80 lb or 75 × 60 lb bags at 4 inches thick, before waste.
How many yards of concrete for a 10×10 slab?
1.23 cubic yards at 4 inches; 1.85 at 6 inches.