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Tyre size convertor: metric to/from imperial

This calculator helps you convert from metric to/from imperial tyre sizes.

For example, 35 x 12.5 x R17 is imperial, and the metric size equivalent is 315 / 70 / R17 – and the tyres are almost identical in size. But the systems are very different, so it’s hard to compare the two sizes.

And yes, in the “metric” format the rim diameter is still in inches! If you need a refresher on tyre sizing, check out the Tyre Help page.

When you’re finished, try the Tyre Size Calculator, or maybe the Towing Weights Calculator.

Select your conversion
Imperial to metric e.g 33x10.5x15 to 275/60/18
Metric to imperial e.g 275/60/18 to 33x10.5x15
Enter imperial tyre measurements
Tyre overall diameterTyre widthRim Diameter
Enter metric tyre measurements
Tyre overall diameterTyre Apect RatioRim Diameter

Your reference:

Whatever you want to name this calculation, e.g. "My Wicked Wheels". Not used in calculations. Only a-Z, 0-9 and - allowed.

Email: Leave blank unless you want results emailed to you. Email not stored or used for any other purpose.


No results to display - select a conversion option and tyre size, then click Calculate

The measurements here are calculated from the general tyre specs. The tyre you want may not be available in those sizes. Also, in practice, actual sizes will vary a little from these measurements, particuarly offroad tyres which have deep tread. Check the exact specs for your selected tyre in your selected size.

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