Find donut shape surface area from major and minor radius
Result
Torus Surface Area
Step-by-Step Derivation
Torus Surface Area Formula
A = 4π²Rr
Torus surface area depends on the circular path around the center and the tube radius. The formula uses both radii to measure the complete outside surface.
⚠Both radii must be positive. Major radius is the distance to the tube center; minor radius is the tube radius.
How Torus Surface Area Works
A torus can be thought of as a circular tube swept around a circular path. The area formula combines the two circular distances.
Major Radius
Distance to the tube center path.
Minor Radius
Radius of the tube cross section.
Outside Surface
The result covers the whole torus surface.
Volume Link
The tool also reports torus volume.
💡 Example: For R=8 and r=2, A=4π²(8)(2)=631.655.
Applications of Torus Surface Area
RingsGasketsCoatings3D Modeling
Frequently Asked Questions
What is a torus surface area calculator?▼
It calculates the outside area of a donut-shaped torus from major and minor radii.
What is the torus surface area formula?▼
The formula is A = 4π²Rr, where R is major radius and r is minor radius.
How do I use this calculator?▼
Enter the major radius and minor radius, then click Calculate.
What is minor radius in a torus?▼
Minor radius is the radius of the circular tube that forms the torus.
Where is torus surface area used?▼
It is used for rings, gaskets, tire-like shapes, coatings, 3D modeling, and engineering estimates.
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