Tire Size Speedometer Calculator

Units

Original (factory) tire → diameter: —

New (current) tire → diameter: —

Format auto-detected per field. Try 225/65R17 (metric), 33x12.50R17 (imperial flotation), 28.5 (inches), or 724 (millimetres). Mix freely.

Indicated speed (what the dashboard shows)

mph

Actual speed

— mph

Speedometer error: — (reads accurate)

Difference: —

Comparison at common speeds

Indicated vs actual speed at common driving speeds
Indicated	Actual	Error

Odometer impact

Indicated odometer reading

Actual distance traveled: —