Tire Size Calculator

Tyre notation (e. g

The calculator uses the standard published formula for tire size. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

This calculator works with inches, percentages, watts. You can enter values in the units shown — the calculator handles all conversions internally.

The core formula is: Sidewall height (mm) = Width × Aspect ratio / 100. Each step in the calculation is shown so you can verify the result manually.