Use this calculator to determine the new offset required when changing your wheel width. Changing rim diameter, for example from 16″ to 17″ makes no difference to offset if you keep the rim width the same. However you may have clearance problems with the rim clearing the strut or spring perch.
First enter your current (or stock) wheel width and offset. Then enter your new wheel width and offset. Next click the calculate button. It will show the difference in clearance between the old and new wheel widths. It will also show how far the outside of the wheel edge will extend or retract compared to the current wheel. If you reduce the inner clearance too much or push the wheel out too far, the tire might not fit, or might rub.
This calculator is for information purposes only and fitment cannot be guaranteed based on this calculator alone. When buying new wheels, always fit the rims on the vehicle before mounting tires to ensure they will fit!
Also check out the tire size calculator to find the right size of tire for your new rims.
Inner Clearance: The change in clearance compared to the current wheel.
Outer Position: The change in the position of the outside of the wheel compared to the current one.
Offset is the difference, in millimetres, between the centre of the wheel and the mounting pad. Positive offset means that the mounting pad is moved closer to the outside of the rim. Negative offset means that the mounting pad is moved toward the inside of the rim from centre. Zero offset means that the mounting pad is exactly at the centre. Here are a couple of diagrams to help explain it…