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
272829303132333435363738394041	6.577.588.599.51010.51111.51212.51313.51414.51515.51616.5	101112131415161718192021222324252627
Tyre overall diameter	Tyre width	Rim Diameter

Enter metric tyre measurements
95105115125135145155165175185195205215225235245255265275285295305315325335345355365375385395405	253035404550556065707580859095	101112131415161718192021222324252627
Tyre overall diameter	Tyre Apect Ratio	Rim Diameter

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Calculate

Results

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.