How to use it
- Enter the volume in cubic yards. If you only know the dimensions, run the concrete calculator first.
- Pick the bag size you plan to buy.
- Keep a small waste allowance for spillage and the bag you'll inevitably tear.
The formula
Bags = (cubic yards × 27 × (1 + waste)) ÷ bag yield
Yields: 40 lb 0.30 ft³ · 50 lb 0.375 ft³ · 60 lb 0.45 ft³ · 80 lb 0.60 ft³
Worked example
| Volume of concrete needed | 0.5 cubic yards |
| Bag size | 80 lb (0.60 ft³) |
| Waste / spillage allowance | 10 % |
Result
| 80 lb bags needed | 25 bags |
| Total weight | 2,000 lb |
| Volume incl. waste | 14.9 ft³ |
| Bags per cubic yard | 45 bags |
| Typical bag cost (U.S. avg.) | $157 |
Tips before you order
- 80 lb bags are the cheapest per cubic foot but heavy to carry and mix by hand.
- A typical portable mixer handles two 80 lb bags at a time.
- Bag prices shown are U.S. averages from a national cost guide; local stores vary.
Questions
How many 80 lb bags of concrete in a cubic yard?
45 bags (27 ft³ ÷ 0.60 ft³ per bag).
When should I order ready-mix instead?
Above roughly 1–1.5 yd³ the labor of mixing 45–70 bags usually outweighs the short-load fee on a ready-mix delivery.