Concrete Foundation Calculator
Find how much concrete you need for a slab or footing
Frequently Asked Questions
Volume = length × width × thickness, converted to cubic yards (÷27 if in cubic feet). Add a 10-15% waste allowance for spillage and an uneven sub-base.
Volume = footing length × width × depth, using the same formula as a slab — a strip footing is just a long, narrow slab.
4 inches is standard for a garage or shed floor; driveways and structural slabs often need 5-6 inches, with rebar or wire mesh reinforcement.
Ready-mix delivered by truck is typically priced per cubic yard. Small pours (under about 1 cubic yard) are often cheaper using bagged concrete mix instead.