Free Tire Size Conversion
Calculator
How to Use the Tire Size Conversion Calculator
Step 1: Enter Your Metric Tire Size
Step 2: Select or Confirm Your Tire Type
Step 3: View the Converted Tire Size in Inches
Step 4: Compare Overall Diameter, Width, and Sidewall
Step 5: Use the Chart to Find Equivalent Standard Sizes
Step 6: Save or Screenshot Your Results
- No login or app required — works in any browser
- Supports most standard tire sizes
- Mobile-friendly layout
- Fast and free with no ads
Enter a metric tire size like 225/65R17:
Illustration of tire dimensions for 225/65R17 format – sidewall height, width, and rim diameter.
Frequently Asked Questions
What does 225/65R17 mean?
225 is the tire width in mm, 65 is the aspect ratio (height % of width), and 17 is the rim diameter in inches.
How is overall diameter calculated?
It's the height of two sidewalls plus the wheel diameter.
Will changing tire size affect speedometer accuracy?
Yes, different diameters will affect your speed readings.
Can I use this size on my car?
Check your vehicle’s manual or a tire specialist before making changes.
What is tread width vs. tire width?
Tread width is contact area; tire width includes sidewalls.