Tire Size Calculator

All misc tools

Calculate tire dimensions and compare tire sizes.

Tire Specs

Width Label

e.g. 245

Aspect Label

e.g. 40

Rim Label

e.g. 18

Results Title

Total Diameter25.72 in653 mm

Sidewall Height3.86 in

Circumference80.79 in

Gearing Impact

Revs Per Mile784.2

About this calculator

Overview

Tire size calculation decodes tire markings (e.g., 225/45R17). Section width, aspect ratio, wheel diameter. Essential for tire shopping and modifications.

💡

Pro Tips

Keeping your new tire diameter within 3% of the original is recommended to avoid rubbing or major speedo errors.
Wider tires provide more grip but increase rolling resistance and fuel consumption.
Fun Fact
Did you know? The first pneumatic (air-filled) tires were invented for bicycles, not cars!

Fun Facts

Formula: Overall Diameter = (Width × Aspect Ratio × 2 / 25.4) + Wheel Diameter