8×10 slab: concrete by thickness
| Thickness | Cu ft | Cu yd | 80 lb bags | 60 lb bags |
|---|---|---|---|---|
| 3.5″ | 23.33 | 0.86 | 39 | 52 |
| 4″ | 26.67 | 0.99 | 45 | 60 |
| 5″ | 33.33 | 1.23 | 56 | 75 |
| 6″ | 40.00 | 1.48 | 67 | 89 |
No waste included in the table.
Worked example
8 ft × 10 ft = 80 sq ft. At 4 inches: 80 × 4 ÷ 12 = 26.67 cu ft, or 0.99 cubic yards. With 10% extra that is 1.09 yd³, or 49 bags of 80 lb mix.
At this size, bagged mix is manageable by hand.
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 8×10 slab?
45 × 80 lb or 60 × 60 lb bags at 4 inches thick, before waste.
How many yards of concrete for a 8×10 slab?
0.99 cubic yards at 4 inches; 1.48 at 6 inches.