Tyre Size Calculator
Decode a tyre code into width, sidewall height, rim size and overall diameter.
Overall diameter and circumference are calculated from the tyre code. Use them to compare sizes or check how a new size changes your speedometer reading.
About this calculator
The Tyre Size Calculator gives you a quick, no-nonsense estimate from the figures you enter. It runs entirely in your browser and is free to use as often as you like — handy for budgeting, comparing options or settling a debate before a trip.
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