Tire Circumference Calculator

Calculate tire diameter, circumference, sidewall height, and revolutions per km/mile in both metric and imperial units.

How to Use the Tire Circumference Calculator

Enter tire size (width/aspect ratio/rim diameter) to calculate diameter, circumference, sidewall height, and revolutions per km.

Sidewall height = Width × (Aspect Ratio / 100). Tire diameter = (Rim diameter × 25.4) + (Sidewall height × 2)

Results are shown in both metric and imperial units. Use this to compare tire sizes before purchasing.