Frustum Volume Calculator

About this calculator

A conical frustum is a cone with its tip sliced off by a plane parallel to the base, leaving two circular faces of different radii, R (larger) and r (smaller), separated by height h. Its volume is V = ⅓·π·h·(R² + R·r + r²), a formula derived by integrating circular cross-sections along the axis, which reduces to the standard cone volume formula when r = 0.

This shape appears constantly in engineering and everyday objects: buckets, lampshades, drinking cups, silos, funnels, and traffic cones are all frustums, and calculating their volume is essential for determining material capacity, liquid volume, or the amount of concrete or sheet metal needed to fabricate one.

Manufacturing and civil engineers designing tanks or hoppers, machinists calculating stock material, students working through solid geometry problems, and hobbyists building custom containers all use this formula. Enter the two radii and height to get the volume.