Concrete Calculator

For slabs, footings and posts — in cubic yards and bags.

How to use this calculator

Enter the length, width and depth in inches, then press Calculate. It returns volume in cubic feet, cubic yards, and the number of 60 lb and 80 lb bags.

What the result means

Cubic yards is what ready-mix companies quote; bags are for smaller jobs. Adding a little extra covers subgrade settlement and waste.

Frequently asked questions

How many bags are in a cubic yard?

Roughly 45 sixty-pound bags or 34 eighty-pound bags per cubic yard.

Should I order extra concrete?

For delivered concrete, add 5-10% — trucks can't top up mid-pour. For bags, add a couple extra.