Tools
Tire size calculator
Enter any tire size to see its real dimensions — sidewall height, overall diameter, circumference, and how many times it turns per mile.
Tire size
That's a — tire.
Sidewall height
—in
Overall diameter
—in
Circumference
—in
Revolutions
—per mile
How to read a tire size
A size like 235/55R18 breaks down into three numbers: the first is tread width in millimetres, the second is the sidewall's aspect ratio — its height as a percentage of that width — and the third is the wheel diameter in inches the tire is built for. Change any of the three and both the sidewall height and the tire's overall rolling diameter shift with it.
For information purposes only. Figures are calculated directly from the size you enter. Always confirm against your vehicle's manufacturer specs before ordering.