About

Concrete Calc is a set of free calculators for estimating concrete quantities for common residential projects: slabs, rectangular and round footings, tubes, curb and gutter, walls, columns, post holes and stairs.

Every calculator uses the same openly documented math. Dimensions are converted to a common unit, the volume is calculated with standard geometric formulas, and a waste allowance you control is added. Bag counts use the selected editable mixed yield. Presets are examples; confirm your product label. Weight uses an explicit editable density.

What we are not

We are not engineers or contractors, and nothing on this site is structural or engineering advice. Use the results as a starting point and confirm with your supplier, contractor or local building authority.

Spotted an error? Please let us know.