Tire size difference calculator

Compares two tire codes by diameter, circumference, and speedometer effect.

How to use

Format: width/profileRrim, e.g. 225/45R17
Current size: OEM or tyre you run now
New size: planned change
Output: diameter delta, circumference delta, speedometer effect

Input data

Unit toggle affects displayed dimensions only; the tire code format stays the same.

Geometric estimate only; actual fit also depends on rim width, offset, and clearance.

Help

Rule of thumb: much more than ~3% diameter change can skew the speedometer and some vehicle systems.

Always confirm OEM guidance and vehicle-specific compatibility before buying.