Tire Size Calculator
Calculate tire diameter, sidewall height, circumference, revolutions per mile, and speedometer error when changing tire sizes.
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How to use this tool?
- 1 Enter the requested data in the fields above carefully.
- 2 Click the calculate button to process the information instantly.
- 3 Analyze the detailed result and the formula explanation presented below.
- 4 You can print, share, or even embed the calculator on your own site for free.
Unlike traditional static calculators, our tools adapt to specific user needs. They include detailed explanations of the formulas used, ensuring transparency in results. Furthermore, our design is focused on user experience, eliminating distractions and focusing on what really matters: your data and conclusions.
Previous Results
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Frequently Asked Questions
Tire size is typically formatted as P225/45R17, where 225 is the width in mm, 45 is the aspect ratio (sidewall height as a percentage of width), and 17 is the wheel diameter in inches.
Tire diameter = wheel diameter + 2 * (tire width * aspect ratio / 100) / 25.4, where the sidewall is converted from mm to inches.
A larger tire diameter reduces speedometer reading (actual speed is higher), while a smaller diameter increases speedometer reading (actual speed is lower). The error can be calculated as a percentage.
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