Cone Frustum Volume Calculator

About this calculator

This calculator finds the volume of a conical frustum — a cone with its pointed top sliced off, leaving two parallel circular faces of different radii — using the formula V = (1/3) × π × h × (R² + R×r + r²), where R and r are the top and bottom radii and h is the height between them.

Frustum shapes are common in real containers and structures: buckets, lampshades, drinking cups, silos, and traffic cones are all frustums rather than full cones, so estimating how much a bucket or silo holds means using the frustum volume formula rather than the simpler cone formula. Engineers, students, and anyone sizing a tapered container use this calculator instead of working through the (R² + R×r + r²) expression by hand.