Wheel Offset Calculator

Your details

Choose mm for the ET (offset) system used in Europe and most modern cars, or inches for the backspacing system common in the US aftermarket.
The measured inside-bead-seat to inside-bead-seat width of the current wheel, in inches. Found on the barrel of the wheel (e.g. 8J).
in
ET (Einpresstiefe) is the distance from the hub mounting face to the wheel centerline. Positive = hub face is outboard of center; negative = hub face is inboard.
mm
Inside-bead-seat width of the new wheel you are considering.
in
ET of the new wheel. Lower or more-negative values move the wheel outward (more poke); higher values tuck the wheel deeper into the arch.
mm
If you are adding a hub-centric spacer, enter its thickness here. A spacer effectively reduces offset by its thickness.
mm
Outer clearance changeVery aggressive
27.7mm

How much the outer edge of the new wheel moves vs. the current one. Positive = moves outward (toward the fender); negative = tucks inward.

Inner clearance change2.3mm
Current backspacing5.38in
New backspacing5.29in
Effective new offset20mm
Fitment assessmentVery aggressive - high risk of fender contact or rubbing
Outer change (mm)27.7
Inner change (mm)2.3

New wheel is significantly more aggressive - verify fender clearance.

  • The new wheel sits 27.7 mm further outward than your current one - inspect fender, arch liner, and any body kit clearances before fitting.
  • Inner clearance increases by 2.3 mm, so the inner edge moves away from the suspension - beneficial for brake caliper and strut clearance.
  • The new backspacing is 5.29 in. Most passenger cars need 3.5-5.0 in of backspacing; trucks and 4x4 builds often use 3.5-4.5 in.

Next stepBefore ordering, also confirm centre bore diameter and bolt pattern match. Fitting an incompatible combination can be dangerous even when the offset numbers look correct.

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