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Torus Calculator
Enter major radius R and tube radius r — volume and surface update instantly.
Formula
V = 2π²Rr² | S = 4π²Rr
Example
O-ring R = 50 mm, r = 3.5 mm → V = 12 127 mm³, S = 6974 mm².
FAQ
What are R and r on a torus?
R is the distance from the torus center to the tube center (major radius); r is the tube radius. R must be larger than r.
What is the volume of an O-ring?
Exactly the torus volume 2π²Rr² — used to estimate seal squeeze volume and elastomer usage.