Wheel Offset Calculator
How much a new offset moves the wheel in or out.
Enter your values
ⓘ Live results
Results
- Moves outward
- 22.7 mm
- Moves inward
- 2.7 mm
- New backspacing
- 6.38 in
- Clearance check
- Inner clearance similar to stock
Quick answer
Changing offset moves the wheel by the offset difference; changing width adds half the extra width to each side of the wheel.
Outward change = (Δwidth ÷ 2) − Δoffset
How to use the Wheel Offset Calculator
- 1Enter the stock wheel width in inches and the offset stamped on the wheel (ET number).
- 2Enter the new wheel width and offset.
- 3Check outward movement against your fender gap.
Worked example
Using the values the calculator loads with:
Inputs
- Stock wheel width8 in
- Stock offset45 mm
- New wheel width9 in
- New offset35 mm
Results
- Moves outward22.7 mm
- Moves inward2.7 mm
- New backspacing6.38 in
- Clearance checkInner clearance similar to stock
Frequently asked questions
What is a negative offset?
A negative offset puts the mounting face behind the wheel centreline, pushing the wheel outward for a deep-dish, wider-track look.
How much poke is safe?
Anything past the fender line risks tire rub, curb damage and, in many regions, a failed inspection. Keep the tire inside the arch at full lock.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.