Is a conical frustum the same as a truncated cone?

For this calculator, yes: it is the part left after cutting a right circular cone by a plane parallel to the base.

Which radius is larger?

Use bottom radius for the larger base and top radius for the smaller base. If your shape is upside down, the volume is the same after swapping the two radii.

Can it handle a cone?

A top radius of zero is the cone limit. For a full cone workflow, use a dedicated cone calculator.

Conical Frustum Volume Calculator

Calculate the volume, slant height, lateral area, and total surface area of a conical frustum from bottom radius, top radius, and height.

Bottom radius (cm)

Top radius (cm)

Height (cm)

Unit

Enter bottom radius, top radius, and vertical height in the same unit. If you measured diameters, divide each diameter by two first.

Diagram orientation

Conical frustum volume

The dominant English intent is a quick truncated-cone or conical-frustum solver with top radius, bottom radius, and vertical height. Competitors also expose slant height and surface area, so this page keeps those outputs visible.

V = \frac{π h}{3} (R^{2} + R r + r^{2})

R is the bottom radius, r is the top radius, and h is the vertical height.

s = h^{2} + (R - r)^{2}

The slant height is needed for lateral surface area.

Common uses

Use case	Most useful output
Bucket, cup, funnel, or planter	Volume plus lateral area and one base when material is needed.
Lampshade or open shell	Lateral surface area.
Closed solid	Total surface area and volume.

If you measured diameters, divide them by two before using this quick volume page, or use the full conical frustum calculator with diameter mode.

Frequently Asked Questions

Sources and References

Calculations are based on the listed reference sources. Links open in a new tab.

Updated: June 2, 2026

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