Tire Size Calculator

A precision tool for automotive engineering and maintenance.

Tire Specification

Standard Tire Code

Width (mm)

Aspect Ratio

Wheel (in)

Geometric Breakdown

Overall Diameter

Wheel Height including Sidewalls

Measurement	Imperial / Metric Value
Section Width	--
Sidewall Height	--
Circumference	--
Revolutions per Mile	--

Pro Tip: If you are changing tire sizes, keep the new "Overall Diameter" within 3% of the factory original to maintain proper speedometer and odometer accuracy.

Code Guide

Input the three parts of your tire code (Width / Ratio R Wheel). We'll instantly derive the total height, circumference, and rolling frequency of the tire.

P: Passenger Vehicle
LT: Light Truck
R: Radial Construction

A larger tire has a larger circumference, meaning it covers more ground per revolution. This is why a taller tire makes your speedometer read lower than your actual speed.

Under-inflated tires have a smaller "effective" radius, which increases fuel consumption and wear. Check your tire pressure monthly to maintain optimal performance!

Tire Size Calculator

Standard Tire Code

Tire Abbreviations

Rolling Logic

Maintenance Tip

Quick Links