Free calculator
Concrete Calculator
Calculate cubic yards of concrete for slabs and pads, with a selectable waste allowance and optional material price.
Your project details
Change the assumptions below to match your project.
Planning estimate only. Actual contractor pricing varies with scope, access, code requirements, permits, labor availability, product brand, warranty and site conditions.
Concrete volume formula
Volume is calculated from length × width × thickness, converted from cubic feet to cubic yards, then increased by your selected waste allowance. One cubic yard equals 27 cubic feet.
Why add waste?
Spillage, uneven subgrade, form variation and ordering increments can leave a project short. A modest waste allowance creates breathing room, but large or structural pours should be verified by the supplier or contractor.
Concrete planning library
See concrete for a 10×10 slab, concrete for a 20×20 slab, concrete cost per yard, and ready-mix vs bags.