Tool
How much concrete do I need?
Pick what you're pouring, enter the dimensions, and I'll tell you how many cubic yards to order or how many bags to buy.
Concrete needed
0 yd³
0 cubic feet
If you mix it with pre-mixed bags:
0
80 lb bags
0
60 lb bags
0
40 lb bags
For a large pour it's almost always cheaper and faster to order the truck (ready mix). Bags make sense for small jobs.
How is it calculated?
Concrete is sold by volume. Every shape comes down to finding its volume in cubic feet, then dividing by 27 to get cubic yards (one cubic yard = 3×3×3 ft).
- Slab / footing / wall: length × width × thickness (convert inches to feet by dividing by 12).
- Round column: π × radius² × height. Radius is half the diameter.
- Square column: width × depth × height.
- Stairs: width × run × rise × (N × (N+1) ÷ 2), where N is the number of steps — each step stacks on the ones below it.
Pouring several identical columns or footings? Set the quantity and the total covers them all.
Need to add up measurements with fractions first? Use the tape measure calculator →