Concrete Calculator

Estimate the cubic yards of concrete and number of bags you need for a patio, driveway or slab.

How this calculator works

Volume = length x width x thickness. Cubic feet divided by 27 gives cubic yards. A 80-lb bag yields about 0.6 cubic feet, a 60-lb bag about 0.45 and a 40-lb bag about 0.3.

Frequently asked questions

How much concrete do I need for a 10x10 slab?

A 10 by 10 foot slab 4 inches thick needs about 1.23 cubic yards, or roughly 1.4 yards with 10% extra.

Estimates for a rectangular slab. Order extra for uneven ground and spillage.