Conical Frustum Volume Calculator
Enter the top radius, bottom radius and height of a conical frustum, a cone with its tip sliced off, to find its volume, slant height and surface areas.
How to find the volume of a frustum
- Enter the bottom radius, the wider circular end.
- Enter the top radius and the height between the two ends.
- Read the volume, slant height and surface areas instantly.
Examples
Bottom 4, top 2, height 6
bottom radius = 4, top radius = 2, height = 6
volume = 175.9292, slant height = 6.3246, lateral area = 119.2151
Equal radii (a cylinder), 3 and 3, height 5
bottom radius = 3, top radius = 3, height = 5
volume = 141.3717, slant height = 5, lateral area = 94.2478
Frequently asked questions
What is a conical frustum?
A conical frustum is what is left when the pointed tip of a cone is sliced off parallel to its base. It has two parallel circular ends.
What is the formula for the volume of a frustum?
The volume equals one third pi times the height times the bottom radius squared plus the bottom radius times the top radius plus the top radius squared.
How is the slant height calculated?
The slant height is the square root of the height squared plus the difference of the two radii squared. It is the slope along the side.
What does the total surface area include?
It adds the slanted side to both circular ends, so it is the lateral area plus pi times the bottom radius squared plus pi times the top radius squared.
Can the radii be equal?
Yes. When the two radii match, the frustum is a cylinder and the volume reduces to pi times the radius squared times the height.
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