Compare metric tire sizes, tire diameter, sidewall height, circumference, revolutions per mile, and speedometer difference. Use this converter to compare tire sizes like 225/65R17, 245/75R16, 275/55R20, and other common tire combinations.
Sidewall height:
width × aspect ratio ÷ 100
Diameter:
wheel diameter + 2 × sidewall height
Circumference:
diameter × π
Revs per mile:
63,360 ÷ circumference in inches
Tire size conversions are useful for comparing replacement tires, wheel upgrades, truck tires, SUV tires, off-road tires, speedometer changes, tire clearance, ride height changes, and alternate tire sizes.
Use this converter as a planning tool, then confirm fitment with the vehicle manufacturer, tire shop, or wheel and tire fitment guide.
Your result compares the original tire size against the new tire size. It shows diameter, sidewall height, tire width, circumference, revolutions per mile, percent difference, and estimated actual speed based on the tire diameter change.
Tire size changes can affect speedometer readings, odometer readings, acceleration, braking, wheel well clearance, suspension clearance, gearing, ABS, traction control, and ride comfort.
It means the tire is 225 mm wide, the sidewall height is 65% of the width, and it fits a 17 inch wheel.
Convert the sidewall height to inches, double it, then add the wheel diameter.
Yes. A larger diameter tire can make the speedometer read lower than actual speed. A smaller tire can make it read higher.
Many people try to stay within about 3% of the original diameter, but the right limit depends on the vehicle and fitment.
No. Tire size math does not guarantee clearance. Always check wheel width, offset, suspension clearance, fender clearance, and manufacturer recommendations.