Cone Volume Calculator

About this calculator

This calculator finds a cone's volume (one-third of π × r² × h — exactly a third of a cylinder with the same base and height), surface area, and slant height (the distance along the cone's side from apex to base edge, found from radius and height via the Pythagorean theorem) using just the radius and height as inputs. The one-third relationship to a cylinder's volume is a classic geometry result that surprises many people the first time they see it demonstrated.

It's used in manufacturing and construction to work out material needed for conical parts — funnels, hoppers, traffic cones, roof spires — and in geometry courses to apply the volume, surface area and slant height formulas to a concrete shape rather than working with them abstractly.