Wheel Circumference Calculator
Get the circumference value to enter into your bike computer, by tire size or measured diameter.
How to use the wheel circumference calculator
- Choose a common tire size, or switch to enter a measured diameter.
- Click Calculate.
- Enter the circumference in mm into your cycling computer.
Tire size affects circumference
Two 700c tires of different widths roll out slightly differently. For best accuracy, measure your own rollout rather than relying on a chart value.
Frequently asked questions
Why does wheel circumference matter?
Bike computers count wheel revolutions, so an accurate circumference is essential for correct speed and distance readings.
How do I measure wheel circumference?
Mark the tire and floor, roll the wheel one full turn with your weight on the bike, and measure the distance between marks — that is your real-world rollout.
Related tools
Gear Ratio Calculator
Work out your gear ratio, gear inches, and development from your chainring, cog and wheel size.
Bike Gear Speed Calculator
See how fast a gear and cadence combination will move you, in km/h and mph.
Speed Distance Time Calculator
Enter any two of speed, distance, and time, and instantly solve for the third.