Concrete Calculator
Pouring a slab, footing, or setting forms? Enter the dimensions and this calculator returns the volume in cubic yards and cubic feet, plus how many 60lb or 80lb bags you need with an optional waste factor. Built for contractors who want the number before they call the supplier.
Estimate
How to use the concrete calculator
- Pick whether you are pouring a slab, footing, or building forms.
- Enter the length and width in feet and the thickness in inches.
- Choose your bag size — 60 lb or 80 lb.
- Read the cubic yards, cubic feet, and bag count. Toggle waste on to pad for overage.
Questions
How many 80 lb bags of concrete are in a cubic yard?
About 45 bags of 80 lb concrete mix make one cubic yard, since each 80 lb bag yields roughly 0.6 cubic feet and a cubic yard is 27 cubic feet.
How much waste should I add for a concrete pour?
Ten percent is a common allowance for spillage, uneven subgrade, and over-excavation. For a tight, well-formed slab you can drop it to 5%.