Wheel Offset / Backspacing Calculator

Convert between offset (ET in mm) and backspacing (inches), and see how much the wheel protrudes from the hub face.

Wheel Width (inches, bead-to-bead)

Offset (mm) — positive or negative

Backspacing

4.787″

Hub-face protrusion

+3.213″

sticks out from hub

How It Works

← Back lipHub faceCenterOuter lip →

← Backspacing →Offset (+pos/-neg)

• Positive offset — mounting face is outboard of center. Wheel tucks inward. Most FWD cars.
• Negative offset — mounting face is inboard of center. Wheel pokes outward. Wide stance / show look.
• Zero offset — mounting face is exactly at the wheel centerline.
• Increasing backspacing by 1″ moves the wheel 1″ inboard.

Common References

OEM FWD (typical)7″ wide · ET+42 → 5.15″ BS

OEM RWD (typical)8″ wide · ET+20 → 4.79″ BS

Muscle car stock7″ wide · ET+6 → 3.74″ BS

Mild stance / poke9″ wide · ET-12 → 4.03″ BS

Deep dish show10″ wide · ET-25 → 4.02″ BS