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Tire Size Calculator

Enter tire sizes you wish to compare:

Original Size
/ R
Example: 235 / 45 R 17
Or: 35 / 12.50 R 20
Alternative Size
/ R
Example: 235 / 45 R 17
Or: 35 / 12.50 R 20

Shows calculated tire dimensions such as width, height, tire profile (sidewall height) and tire circumference. If two tire sizes are entered for comparison the column on the right will show the difference of the two in inches, millimeters as well as percentage difference.
Tire Size Calculator supports both Metric and Flotation sizes and can be used to compare tire sizes in both systems.

                            Original Tire
Imperial (In) Metric (Mm)
Section Width
Sidewall Height
Overall Diameter
Circumference
Revs/Mile Revs/Km
Alternative Tire
Imperial (In) Metric (Mm)
Revs/Mile Revs/Km
Difference Difference(%)
Imperial (In) Metric (Mm) %
Revs/Mile Revs/Km

* We recommend staying within 3% difference from overall diameter of your original (OEM) tire size when selecting an alternative size.

Speedometer reading vs. actual speed with alternative size tires on.
Speedometer reading: Actual speed:
Speedometer reading: Actual speed:
Using different tire sizes can cause speedometer inaccuracy. This speedometer variance section of Tire Size Calculator shows the speedometer reading difference in MPH, KM/H as well as percentage difference for two tire sizes entered to compare.

* Tireconvert.com tire size calculator is intended for informational use only. Actual tire dimensions may vary slightly depending on a tire brand and model. Actual dimensions should be obtained from the manufacturer.