How it's worked out
- Area: 10 × 10 = 100 sq ft
- Volume: 100 sq ft × 4 in ÷ 12 = 33.3 cu ft
- Add 10%: 33.3 × 1.1 = 36.7 cu ft
- Cubic yards: 36.7 ÷ 27 = 1.36 yd³
- 80 lb bags: 36.7 ÷ 0.6 cu ft per bag = 62 bags
10x10 slab at other thicknesses
| Thickness | Cubic yards | 80 lb bags | 60 lb bags |
|---|---|---|---|
| 4 in | 1.36 | 62 | 82 |
| 5 in | 1.7 | 77 | 102 |
| 6 in | 2.04 | 92 | 123 |
4 inches suits patios, sheds and walkways. Driveways and garage floors usually get 5 to 6 inches.
At 1.36 yards, ready-mix delivery is usually cheaper and much less work than mixing 62 bags by hand. Most suppliers deliver in quarter or half yard steps, so round up when you order.
Other common sizes
- 10 × 10 ft
- 10 × 12 ft
- 10 × 20 ft
- 12 × 12 ft
- 12 × 20 ft
- 12 × 24 ft
- 16 × 16 ft
- 20 × 20 ft
- 20 × 24 ft
- 24 × 24 ft
- 30 × 30 ft
More detail: How Many Bags of Concrete Do I Need? (Chart + Examples)