Tyre Size Calculator
The Tyre Size Calculator is a free UK tool that helps you work out tyre size without the guesswork. It is built for British figures and is current for the 2026/27 period, with the method used shown in full below.
Tyre Size Calculator
The interactive calculator will appear here. The page content, method and FAQs below are complete.
How the Tyre Size Calculator works
This calculator uses an established formula to produce its result. Enter your figures and the answer is worked out for you. Method note: Diameter from tyre code.
Our method
This page is maintained as a UK reference tool. The figures and formula behind it are checked against current official guidance, and the approach is set out plainly so you can see how a result is reached. If a rate changes - for example at a Budget or a new tax year - the page is updated and the review date below is refreshed.
Frequently asked questions
Is the Tyre Size Calculator free to use?
Yes. Every calculator on Online Calculators is free, with no sign-up and no limit on how often you use it.
Is the Tyre Size Calculator accurate for the UK?
The Tyre Size Calculator is built specifically for UK figures and conventions. Rate-sensitive tools are reviewed against current official guidance each tax year.
How is the result worked out?
It uses an established formula to produce its result. Enter your figures and the answer is worked out for you. Method note: Diameter from tyre code.
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