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Tire size calculator
Compare two metric tire sizes and see their nominal measurements and estimated speed difference.
How do I compare tire sizes?
Enter both metric sizes, such as 205/55R16, and your indicated speed. Results are estimates; always confirm fitment with your vehicle and tire maker.
Frequently asked questions
How do I compare tire sizes?
Enter both metric sizes, such as 205/55R16, and your indicated speed. Results are estimates; always confirm fitment with your vehicle and tire maker.
Are my tire sizes uploaded?
No. This calculator runs in your browser. It does not send your entries to a server.
Will this replacement tire fit my vehicle?
Nominal-size estimate only. It does not confirm fitment, safety or legal compliance. Real dimensions vary by tire model and wear.
How is actual speed estimated?
Dashboard speed is multiplied by the ratio of new to current nominal tire diameter. Real tire sizes vary, so this is an estimate.