How many bags of concrete for a 10×10 slab?
A 10 × 10 ft slab at the common 4-inch thickness needs about 1.23 cubic yards of concrete — roughly 56 bags of 80 lb mix (or 74 × 60 lb, or 111 × 40 lb). At this size, many people order a small ready-mix load instead of mixing dozens of bags by hand.
The math
- Area = 10 × 10 = 100 sq ft
- Volume = 100 × (4 ÷ 12) = 33.3 cu ft = 33.3 ÷ 27 = 1.23 cubic yards
- Bags = 33.3 cu ft ÷ the bag's yield (80 lb = 0.60 cu ft) = ~56 bags of 80 lb
By slab thickness
| Thickness | Cubic yards | 80 lb bags |
|---|---|---|
| 4 inches | 1.23 cu yd | ~56 |
| 5 inches | 1.54 cu yd | ~70 |
| 6 inches | 1.85 cu yd | ~84 |
Always buy a little extra (about 5–10%) for uneven subgrade and spillage.
Different size or thickness?
The concrete calculator gives cubic yards and the bag count for any slab, footing, or post — with an editable price.
Open the Concrete CalculatorBags or ready-mix?
A 10×10 slab sits right at the ~1 cubic yard crossover where a ready-mix truck starts to beat bags on both effort and a clean, continuous pour. Mixing 56 bags by hand is a serious workout and risks cold joints if batches set at different rates. Unless a truck can't reach the site, ready-mix is usually the better call here — see bags vs. ready-mix concrete for the full trade-off.