About Tire Size Guide
Last checked 12 October 2026Published by Sidewall GuideFormulas follow the Tire and Rim Association and ETRTO size conventions
Tire Size Guide is published by Tire Size Guide Publishing. It provides tire size comparisons and guides to help readers understand calculated changes in tire dimensions.
Editorial responsibility
Editor
Noam Cohen built the calculators, writes the guides and checks every figure against the published formulas and the sources listed on this site. No tire brand or retailer pays for placement or wording.
Calculation checks
How we check the numbers
The formulas follow Tire and Rim Association (T&RA) and European Tyre and Rim Technical Organisation (ETRTO) conventions. Worked examples are re-checked by automated tests whenever a formula changes. Read the full methodology for formulas, rounding rules and sources.
Scope
What this site does not do
This site does not sell tires or confirm fitment for a vehicle. Its size calculations are estimates and do not account for every vehicle-specific clearance or requirement.
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