How Much Concrete for a 10x10 Slab? (Bags & Yards)
A 10x10 slab at 4 inches deep needs 1.23 cubic yards or 74 bags of 60 lb concrete. Full math, charts and bags vs ready-mix advice.
Quick answer: A 10×10 ft slab at 4 inches deep needs 1.23 cubic yards — about 74 bags of 60 lb concrete (with 10% extra). Use the concrete calculator for any size.
Concrete math for a 10x10 slab
Concrete is ordered by volume. The formula never changes:
Cubic feet = length (ft) × width (ft) × depth (ft)
Step 1 — convert depth to feet
4 inches ÷ 12 = 0.333 ft. A 10×10 slab: 10 × 10 × 0.333 = 33.3 cu ft.
Step 2 — convert to cubic yards
1 yard = 27 cu ft. 33.3 ÷ 27 = 1.23 cubic yards.
Step 3 — count bags
| Bag size | Volume per bag | Bags per 33.3 cu ft |
|---|---|---|
| 40 lb | 0.30 cu ft | 111 bags |
| 60 lb | 0.45 cu ft | 74 bags |
| 80 lb | 0.60 cu ft | 56 bags |
Bags shown with 10% extra for spillage and uneven ground.
Common slab sizes at 4 inches deep
| Slab | Volume | Cubic yards | 60 lb bags |
|---|---|---|---|
| 8×8 (shed pad) | 21.3 cu ft | 0.79 | 52 |
| 10×10 (patio) | 33.3 cu ft | 1.23 | 74 |
| 10×12 | 40 cu ft | 1.48 | 89 |
| 12×12 | 48 cu ft | 1.78 | 107 |
| 10×20 (walkway) | 66.7 cu ft | 2.47 | 148 |
Bags or ready-mix?
- Under 1 yard: bags win — no delivery minimum, mix as needed
- 1-2 yards: borderline; bags work but expect a long day
- Over 2 yards: order ready-mix — cheaper per yard and one pour instead of 100+ bags
FAQ
How many 80 lb bags in a cubic yard?
An 80 lb bag makes about 0.6 cu ft, so a yard (27 cu ft) needs about 45 bags.
Is 4 inches enough for a shed slab?
Yes for light storage. Add rebar and go 5-6 inches if you park vehicles or store heavy equipment.
Do I need to add 10% extra concrete?
Yes — ground is never perfectly level. 5-10% extra covers low spots and spillage.
Need a different size?
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