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Results
Enter your dimensions above and the results appear here.
About the Torus Calculator
The torus calculator is a free online tool: volume and surface area of a ring solid. Enter major radius (R) and tube radius (r) and the results update instantly, alongside a labelled diagram so you always know which measurement goes where.
Choose your input unit (mm, cm, m, km, in, ft or yd) and optionally show the results in a different one: lengths, areas and volumes are converted correctly. Every answer shows the formula behind it, and the calculation runs in your browser, so nothing is uploaded.
Torus Calculator example
Major radius (R) = 6 cm
Tube radius (r) = 2 cmVolume = 473.741 cm³
Surface area = 473.741 cm²
Inner diameter = 8 cm
Outer diameter = 16 cmHow to use the Torus Calculator
- Pick the unit your measurements use. All dimensions must share the same unit.
- Enter major radius (R) and tube radius (r). Focus a field to highlight the matching label on the diagram.
- Read the results as you type. The largest card is the main answer; the others are the related measurements.
- Copy a single value, copy everything, or share a link that keeps your inputs.
Torus Calculator FAQ
What formulas does the torus calculator use?
V = 2π²Rr²; SA = 4π²Rr; Outer diameter = 2(R + r).
Can I use different units?
Yes. Pick the input unit and, if you like, a different output unit. Area results are shown in squared units and volumes in cubed units.
Is this torus calculator free and private?
Yes. It is free with no sign-up, and calculations happen on your device, so your numbers are never sent to a server.
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