Result—
Tyre dimensions are nominal. Actual dimensions vary by tyre model, wheel width, pressure and load. Check manufacturer fitment guidance.
CALCULATOR GUIDE
How tyre size comparison works
Tyre codes such as 225/45 R18 describe width, sidewall aspect ratio and wheel diameter. The calculator converts both sizes into overall diameter and circumference, then shows the percentage difference.
Actual tyre dimensions vary slightly between manufacturers. Always check vehicle and tyre manufacturer fitment guidance before changing size.