Concrete Calculator

Pouring a patio slab, a set of structural columns, or foundation footings means committing to a concrete order before the truck arrives, and getting that number wrong costs money in either direction. The figure that matters is cubic yards, and pinning it down before mid-2026 carries extra weight given the roughly 4.5% rise in concrete prices projected for that period. Ordering short stalls the job; ordering long pays for material that hardens in the chute.

Each shape has its own volume formula. A slab is Length x Width x Thickness; a round column is Pi x (Radius)^2 x Height; a footing is Length x Width x Depth. Dimensions get converted to feet, the result is expressed in cubic yards, and the total is rounded up to the nearest quarter cubic yard. That rounding is deliberate, since it absorbs the small losses to waste and spillage that occur on every pour.

On top of that rounding, add a 5-10% waste factor, more toward the upper end when the forms are intricate or the subgrade sits unevenly. The errors that bite hardest are an understated slab thickness or a miscalled column diameter, both of which leave you short mid-pour. Keep every measurement in the same unit, all feet or all inches, and convert only once, because mixing units is where the largest mistakes creep in.