Concrete Bag Coverage Chart: Yield & Bags Per Yard
A 40-lb bag of concrete yields about 0.30 cubic feet, a 60-lb bag about 0.45 cubic feet, and an 80-lb bag about 0.60 cubic feet. It takes roughly 90, 60, and 45 bags respectively to make one cubic yard (27 cubic feet). To find how many bags you need, calculate your project's volume in cubic feet and divide by the yield of your bag size.
Bagged concrete is the go-to for small pours — fence posts, footings, small pads, and repairs — but the bag doesn't tell you how much volume it actually fills once mixed. This coverage chart translates bag weight into cubic feet so you can buy the right number and avoid a mid-job trip to the store.
Below you'll find the yield for every common bag size, how many bags make a cubic yard, and a ready-reckoner for typical projects like slabs and post holes.
Key takeaways
- A 60-lb bag yields ~0.45 ft³; an 80-lb bag yields ~0.60 ft³.
- It takes ~60 sixty-pound bags or ~45 eighty-pound bags per cubic yard.
- Find bags needed = project volume (ft³) ÷ bag yield.
- Above about one cubic yard, ready-mix delivery is cheaper than bags.
- Always buy a couple of extra bags for waste and spillage.
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Concrete bag yield chart
Each bag of pre-mixed concrete yields a set volume once water is added. The heavier the bag, the more cubic feet it fills — and the fewer bags you need for the same pour.
| Bag size | Yield (ft³) | Bags per cubic yard | Bags per 10 ft³ |
|---|---|---|---|
| 40 lb | 0.30 ft³ | ~90 | ~34 |
| 50 lb | 0.375 ft³ | ~72 | ~27 |
| 60 lb | 0.45 ft³ | ~60 | ~23 |
| 80 lb | 0.60 ft³ | ~45 | ~17 |
How to use the chart
First, calculate your project volume: multiply length × width × thickness in feet to get cubic feet. Then divide that by the yield of the bag size you plan to buy, round up, and add two or three bags for waste. For example, a 3 ft × 3 ft pad at 4 inches thick is 3 × 3 × 0.33 = 3 cubic feet, which is about 7 eighty-pound bags.
Bags needed for common projects
| Project | Volume | 60 lb bags | 80 lb bags |
|---|---|---|---|
| Fence post hole (10"×24") | ~0.9 ft³ | 2 | 2 |
| 3×3 ft pad, 4" thick | ~3 ft³ | 7 | 5 |
| Sonotube 8"×4 ft | ~1.4 ft³ | 3 | 3 |
| 10×10 ft slab, 4" thick | ~33 ft³ | 74 | 56 |
When to switch to ready-mix
Mixing bags by hand is fine up to about one cubic yard (roughly 45–60 bags). Beyond that, the labor, water, and risk of cold joints between batches make ready-mix delivery both cheaper and more reliable. If your project needs more than a cubic yard, price out a ready-mix truck before buying pallets of bags.