Concrete Calculator

Calculate how much concrete you need in cubic yards, bags, and cost for slabs, footings, and walls.

Cubic Yards Needed is Length multiplied by Width multiplied by Depth (converted from inches to feet), divided by 27 to convert cubic feet into cubic yards -- because all three dimensions multiply together into the same volume, a given percentage change to Length, Width, or Depth moves Cubic Yards Needed by that same proportional amount no matter which one you adjust. Estimated Cost carries that same relationship one step further: it's Cubic Yards Needed (plus a fixed 10% waste allowance) multiplied by Cost per Cubic Yard, so all four inputs -- Length, Width, Depth, and Cost per Cubic Yard -- move Estimated Cost by an equal proportional amount for an equal proportional change, since each one enters the formula as a simple multiplying factor. The bag counts (60 lb and 80 lb) convert Cubic Feet directly into however many pre-mixed bags would fill the same volume, useful for smaller hand-mixed pours where ready-mix delivery isn't practical. With 10% Waste automatically adds a standard contractor buffer for spillage and over-excavation -- order that larger figure from a ready-mix supplier, not the raw Cubic Yards Needed number. This calculator assumes a simple rectangular slab, footing, or wall section; it doesn't account for rebar volume displacement, formwork losses, or non-rectangular pours.