Torus Surface Area Calculator
Enter the centerline radius R and tube radius r to calculate A = 4π²Rr locally.
A QUICK WALKTHROUGH
How to use this tool
- Enter a positive major radius R.
- Enter a positive minor radius r smaller than R.
- Calculate and copy the surface area.
Radius definitions
The major radius R runs from the torus center to the center of the tube. The minor radius r is the radius of the tube itself.
Ring-torus domain
This calculator requires R > r > 0 and uses A = 4π²Rr. Enter both radii in the same unit; the result uses its square.
GOOD TO KNOW
Common questions
Can I enter outer and inner diameters?
Convert them first: R = (outer diameter + inner diameter) / 4 and r = (outer diameter − inner diameter) / 4.
Is the calculation uploaded?
No. It runs locally in your browser.