Wheel Offset Calculator
Free wheel offset calculator. Compare stock and new wheel width and offset to see how far the wheel moves outward and inward and whether it clears the fender.
About This Free Online Wheel Offset Calculator
Our free wheel offset calculator shows exactly how a new set of wheels will sit compared to stock. Enter the stock wheel width and offset, then the new wheel width and offset, and the tool returns how far the wheel face moves outward and inward (in mm), the new and stock backspacing, and the resulting fender clearance so you can tell whether the wheels will fit or rub. Everything runs in your browser — perfect for car, truck and SUV fitment planning.
Features of Our Wheel Offset Calculator
- Outer and inner position change in millimeters
- New and stock backspacing in inches
- Fender clearance check (fit or rub risk)
- Handles any wheel width and ET offset
- Great for planning wheel spacers or new wheels
- 100% client-side and private — instant results, no signup
How to Use the Wheel Offset Calculator
Using this tool is simple and requires no signup or registration. Follow these steps:
- Enter your stock wheel width (in) and offset (mm, ET).
- Enter the new wheel width and offset you are considering.
- The tool compares centerlines and backspacing.
- Read off the outer/inner change and fender clearance.
Frequently Asked Questions About Wheel Offset Calculator
What is wheel offset (ET)?
Offset (ET) is the distance in millimeters between the wheel's mounting hub and its true centerline. Positive offset tucks the wheel inward toward the car; negative offset pushes it outward. Changing width or offset moves the wheel in or out.
How do you calculate backspacing from offset?
Backspacing = (wheel width + 1) ÷ 2 + offset ÷ 25.4, where offset is in mm and width in inches. The +1 accounts for the typical rim lip. The calculator returns backspacing for both your stock and new wheels.
Will wider wheels stick out more?
If you keep the same offset, adding width pushes the wheel equally outward and inward. To keep the outer face in the same spot on a wider wheel, choose a more positive offset. The calculator shows the exact outer and inner change.
How much clearance do I need to avoid rubbing?
Most setups want at least 5 to 10 mm of fender clearance, more if you drive hard or run a lower offset. The calculator flags the clearance and labels it as a fit or rub risk.
Is this wheel offset calculator free?
Yes, completely free with no signup. All maths runs in your browser — nothing is uploaded or tracked.
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