Tools
Wheel Offset Calculator
Compare wheel offset (ET) and width side by side — see how much your new wheels will poke or tuck, change in inner suspension clearance, and ET ↔ backspacing conversion. Then book a fitment check with AutoCraze.
Existing wheel
New wheel
Quick converter - ET / Backspacing
Have AutoCraze verify clearance for your build
Fitment is part maths, part experience. Send us your stock and target wheel specs and we'll confirm whether you'll need spacers, guard rolling or different offset — and put together a quote on wheels that suit your car.
An AutoCraze fitment expert will be in touch shortly. Call us on 1300 092 727.
What is wheel offset?
Offset (ET) is the distance, in millimetres, from the wheel's hub mounting face to its true centreline.
Positive ET = mounting face outboard of centreline (tucks into guard). Negative ET = mounting face inboard (pokes out).
Backspacing: BS (in) = (Width / 2) + 0.5 + (ET / 25.4). Stay within +/-5 mm of factory ET; beyond +/-10 mm may need VSB 14 LS9 signoff.