Tire Size Calculator
Compare two tire sizes and the speedometer difference.
| Diameter | Circumference | Sidewall | Width | |
|---|---|---|---|---|
| 205/55 R16 | 631.9 mm | 1,985 mm | 112.8 mm | 205 mm |
| 225/45 R17 | 634.3 mm | 1,993 mm | 101.3 mm | 225 mm |
Runs entirely in your browser. Nothing is sent anywhere.
How it works
- 1Enter your values.
- 2See the result update instantly as you type.
- 3Change any value to compare scenarios.
About this tool
Tire Size Calculator: Compare two tire sizes and the speedometer difference. Type your numbers and the result is calculated instantly — no button to press, nothing to install. All math runs locally in your browser, so the values you enter are never sent anywhere.
Example
| Input | |
|---|---|
| Current tire (e.g. 205/55 R16) | 205/55 R16 |
| New tire | 225/45 R17 |
| Result | |
| Speedometer difference | 0.38 % |
| At an indicated 100 km/h you drive | 100.4 km/h |
How do I use the Tire Size Calculator?
Enter your values. See the result update instantly as you type. Change any value to compare scenarios.
Is the Tire Size Calculator free?
Yes. It is completely free with no sign-up, no usage limits and no watermark.
Is my data sent to a server?
No. Everything is calculated locally in your browser. Nothing you enter is uploaded, logged or stored.
Does it work on my phone?
Yes. It works in any modern browser on Android, iPhone, iPad, Windows, Mac and Linux — no app needed.
