How to use the Sphere Cubic Feet Calculator
- Measure diameter across the centre and divide it by two to obtain radius. Choose hemisphere for exactly half of a sphere.
- Choose the shape mode, where available, and a unit for each dimension. Enter the number of identical objects.
- Select Calculate. Review the result and its working; if you change an input, calculate again before copying or sharing.
Sphere formula
Convert each length to feet, apply the displayed solid-volume formula, then multiply by the number of identical objects.
4 × π × r³ ÷ 3
What the terms mean
- Radius
- A measured length in the selected unit; it is converted to feet before volume is calculated.
- Number of identical items
- The whole-number count of objects with the same entered dimensions.
Sphere worked examples
Measure a spherical object
A sphere has a radius of 1 ft. Find its full solid volume.
- 4 × π × r³ ÷ 3
- radius = 1 ft
- 4.18879 ft³ × 1 = 4.18879 ft³
Answer: 4.18879 ft³. Cubic yards: 0.15514 yd³; Litres: 118.61333 L.
Estimate a hemispherical dome
A half-sphere has a radius of 2 ft. Select hemisphere rather than full sphere.
- 2 × π × r³ ÷ 3
- radius = 2 ft
- 16.755161 ft³ × 1 = 16.755161 ft³
Answer: 16.755161 ft³. Cubic yards: 0.620562 yd³; Litres: 474.453319 L.
Sphere Cubic Feet Calculator FAQs
What if I measured the diameter?
Halve it first, retaining the same unit. A diameter of 10 inches gives a radius of 5 inches.
Does hemisphere mean any rounded dome?
No. It means exactly half a sphere. A dome with a different height needs a spherical-cap model.
Measurement guide for Sphere
Measure the diameter through the centre, then halve it. Choose hemisphere only when the shape is exactly half a sphere.
Assumptions and limits
The hemisphere calculation assumes a cut through the centre. A shallow spherical cap or an ellipsoid requires other dimensions.
Check your result
Check the dimensions converted to feet in the working. For similar solids, doubling every dimension increases volume by a factor of eight.