Bags or a truck?
At this size a ready-mix truck is the sensible choice. Mixing 500 bags by hand is a long, heavy day, and the first batches start to set before the last ones are placed.
Concrete slab charts · 30 × 30 ft
How much concrete for a 30×30 slab?
A 30 × 30 ft slab 4 inches thick needs 11.11 cubic yards of concrete (300.0 cubic feet), or about 500 bags of 80 lb premix. Add 5–10% for waste. Other thicknesses are in the table, or adjust the calculator below.
Units
30 × 30 ft slab by thickness
Exact volumes without waste. Bag counts are rounded up.
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | Metric |
|---|---|---|---|---|---|
| 3 in | 8.33 yd³ | 225.0 ft³ | 375 | 500 | 6.37 m³ |
| 4 in | 11.11 yd³ | 300.0 ft³ | 500 | 667 | 8.50 m³ |
| 5 in | 13.89 yd³ | 375.0 ft³ | 625 | 834 | 10.62 m³ |
| 6 in | 16.67 yd³ | 450.0 ft³ | 750 | 1000 | 12.74 m³ |