How to use the torus calculator
Find volume and surface area of a torus. Enter major radius, minor radius in the fields above; the volume, surface area are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- R — Major radius
- r — Minor radius
Worked example
With major radius = 10, minor radius = 3, the calculator gives volume ≈ 1,776.529; surface area ≈ 1,184.353.
Frequently asked questions
What is the formula for the torus calculation?
Volume = 2 × π × π × R × r × r. Surface area = 4 × π × π × R × r. Here R is major radius, r is minor radius.
What inputs do I need for the torus (donut) calculator?
You need major radius, minor radius. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.