Tire Diameter Calculator
Calculate the overall outer diameter of your tire from its metric size code. Results in inches, millimeters, and centimeters.
How It Works
Formula
Diameter (in) = (2 × width × aspectRatio / 2540) + rimDiameter
This formula calculates the sidewall height in inches (width × aspect / 2540) and doubles it (top + bottom sidewall) before adding the rim diameter.
Frequently Asked Questions
What is overall tire diameter?
Overall tire diameter is the full outer diameter of the mounted, inflated tire — rim diameter plus twice the sidewall height.