WheelTire Size Tools for
Mechanics & Drivers
Calculate tire dimensions, compare sizes, and understand what those numbers on your sidewall actually mean. Free, fast, no sign-up.
Tools
Tire Size Calculator
Enter width, profile, and rim size to get overall diameter, sidewall height, circumference, and revolutions per mile or km. Switches between metric and imperial instantly.
Calculate now →Tire Size Comparison
Compare two tire sizes side by side. See the diameter difference, which size is taller or wider, and how much your speedometer reading will be off.
Compare sizes →How to Read Tire Size
Learn what every number in a tire size code like 205/55R16 means. Illustrated guide with FAQ — perfect for first-timers buying tires or swapping rims.
Imperial & Metric
Switches between inches and millimeters based on your location. Preference saved automatically.
Works on Any Device
High-contrast display readable in bright sunlight.
Instant Results
No server calls for calculations. Everything runs locally in your browser for instant feedback.
Visual Diagrams
Diagrams update in real time to show exactly what your tire will look like.