Offset Calculator
Tyre Size Calculator

Use our tyre size calculator to calculate the diameter, sidewall, circumference, and revolutions per kilometer of any tyre. Input your existing tyre size in metric or imperial sizing, then the new tyre size, results will be displayed below.

Current Wheel Specs
Width
Inches
Current Offset
MM
New Wheel Specs
New Width
Inches
New Offset
MM
Results
Inner Clearance
(the inside of the wheel to the strut housing)
Outer Position
(position of the outside edge of the wheel)
Enter Your Tyre Sizes Below
Current Tyre Size (E.g 205/45 R17)
Width(mm)
/
Aspect Ratio%
R
Inch(Rim)
New Tyre Size (E.g 205/45 R17)
Width(mm)
/
Aspect Ratio%
R
Inch(Rim)
Your Current Tyre
Your New Tyre
Overall rolling diameter Measurement
Sidewall height
Circumference
Revolutions per/km
Actual Speed
100KM/H
Speedometer under-read or over-read