Free volume calculator and concrete slab helper: rectangular L×W×H, cylinder πr²h, cone ⅓πr²h, sphere 4/3πr³—browser math with consistent units, no login.
Select a shape and enter positive dimensions in one unit system. Rectangular uses L×W×H, cylinder πr²h, cone (1/3)πr²h, sphere (4/3)πr³. Results update after you press Calculate so you can change one dimension and compare estimates without reloading the page.
For a simple rectangular pour, use rectangular mode with length, width, and thickness. It does not estimate bags, waste factor, or rebar.
V = π × radius² × height. Enter radius, not diameter.
V = (1/3) × π × radius² × height for a right circular cone.
V = (4/3) × π × radius³. Only radius is required.
No. Math runs in your browser. Inputs are not stored as uploaded file content for analytics.
Yes. Free to use with no login required on Power Tools.
Sibling tools such as Square Footage Calculator. Labels are tool names; tapping opens that page. Pair with Unit Converter when plans mix metric and imperial labels.