A 10 x 10 ft slab at 4 inches thick holds 10 x 10 x 4 / 12 = 33.3 cubic feet, or 1.23 cubic yards.
Bag counts
| Bag size | Yield | Bags (no waste) | With 10% waste |
|---|---|---|---|
| 80 lb | 0.60 ft³ | 56 | 62 |
| 60 lb | 0.45 ft³ | 75 | 82 |
| 40 lb | 0.30 ft³ | 112 | 123 |
Bags or ready-mix?
At 1.23 yards, ready-mix is worth pricing. Many plants have a minimum load and a short-load fee, so compare against about 62 bags of 80 lb mix at your local bag price. Mixing 62 bags by hand is hard work; renting a mixer helps.
Try the slab calculator with your own size.