Tire Circumference
Calculator
Calculate geometric tire circumference and revolutions per mile from a measured or nominal diameter, with metric and imperial results.
Your setup
Your results
CalculatedRevolutions per distance are inversely proportional to circumference.
Geometric circumference is not necessarily loaded rolling circumference.
How the calculation works
Follow the formula and keep the input units consistent at every step.
circumference = π × diameter; rev/mile = 1609.344 / circumference(m)- Measure diameter or use the nominal tire-size result.
- Multiply by π.
- Divide distance per mile or kilometer by circumference.
A Worked Example
A 13-inch tire has geometric circumference 40.84 inches (1.03735 m), about 1,551.40 revolutions per mile.
What Your Result Means
Revolutions per distance are inversely proportional to circumference.
Assumptions & Limitations
Geometric circumference is not necessarily loaded rolling circumference.
Common Mistakes
Do not use radius in the diameter field.
Questions about this calculation
Which values should I enter?
Measure diameter or use the nominal tire-size result. Do not use radius in the diameter field.
How should I interpret the result’s precision?
Displayed results are rounded for readability. Intermediate calculations retain floating-point precision; extra displayed decimals do not improve your input accuracy.
Can I use metric units?
Yes. Select Metric above the calculator to convert your inputs. Results always state their units. Tire-size designations keep their conventional mm and inch units.
What are the main limitations?
Geometric circumference is not necessarily loaded rolling circumference.
Method, sources & relevant guides
Angular speed and tangential speed. Gear reductions follow tooth engagement and conservation of rotation count.
OpenStax — University Physics: rotation with constant angular accelerationMethod documentation updated October 18, 2026. Independent professional review has not been claimed. Read the calculation and review policy.