Maths & numbers
Conical frustum calculator
Find the volume and surface areas of a truncated right circular cone.
A clear answer. Here’s how.
For a right circular frustum, volume = πh(R²+Rr+r²)/3. Slant height = √[h²+(R−r)²]; lateral area = π(R+r) × slant height. Adds the two circular end areas for the closed total. The radii may be equal (a cylinder), and either can be zero (a cone); they cannot both be zero.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Bottom radius
- 5
- Top radius
- 3
- Perpendicular height
- 4
Example result
- Volume
- 205.250720035
- Slant height
- 4.472135955
- Lateral area
- 112.397035697
- Two end areas
- 106.814150222
- Closed total area
- 219.211185919