Cubic yards, cubic feet, and bags — instantly
* Includes 10% extra for waste & spillage
Concrete is measured in cubic yards when ordering from a ready-mix truck. For smaller jobs, it comes in bags. Use this calculator to find exactly how much you need, then add 10% for waste.
| Shape | Formula |
|---|---|
| Slab | Length × Width × Thickness ÷ 27 |
| Footing | Length × Width × Depth ÷ 27 |
| Square Column | Width² × Height ÷ 27 |
| Round Column / Post Hole | π × (Diameter/2)² × Depth ÷ 27 |
| Bag Size | Bags per Cubic Yard |
|---|---|
| 40 lb bag | ~90 bags |
| 60 lb bag | ~60 bags |
| 80 lb bag | ~45 bags |
If your project needs more than 1 cubic yard, ordering ready-mix concrete is usually cheaper and easier. For smaller projects like fence posts or small slabs, bagged concrete from a home improvement store makes more sense.