Volume of Rectangle
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Conical Frustum Volume Calculator

Find the volume of a cone with its top sliced off.

V = \frac{\pi h}{3} (R^2 + Rr + r^2)
r1 = ?
r2 = ?
h = ?
Diagram updates instantly as you type.

What is a Conical Frustum?

A cone with the top cut off.

A conical frustum is a frustum created by slicing the top off a cone (with the cut made parallel to the base). It is the shape of a typical drinking glass, bucket, or lampshade.

Key Information
Shape Focus
conical frustum volume calculator

How to Find the Volume of a Conical Frustum

You need the radii of both bases and the height.

1
Measure the radius of the bottom base.
2
Measure the radius of the top base.
3
Measure the vertical height between the two bases and apply the formula.

Conical Frustum Volume Formula

The equation for a truncated cone.

V = \frac{π h}{3} (R^2 + Rr + r^2)
V Volume
r1 Bottom Radius
r2 Top Radius
h Height

Where 'h' is height, 'R' is the radius of the bottom base, and 'r' is the radius of the top base.

Frequently Asked Questions

What is the difference between a cone and a frustum?

A cone comes to a single point (apex). A frustum has a flat top where the apex would have been.

Can I use the slant height instead of vertical height?

No, the volume formula specifically requires the vertical height between the two parallel bases.

What if R and r are equal?

If both bases are identical, the shape is no longer a frustum, it's a cylinder, and the formula simplifies to the cylinder volume formula.

Is a bucket a conical frustum?

Yes, standard round buckets are perfect examples of conical frustums.