Convert wheel offset to backspacing and back. Enter your wheel width and offset to get backspacing and frontspacing, or enter backspacing to find the offset. Essential when comparing wheels that list specs differently.
Wheel Cross-Section
Side view of the wheel barrel — the mounting face position sets backspacing (toward the suspension) and frontspacing (toward the street).
Offset vs backspacing
Offset is the distance (in mm) from the wheel's centerline to its mounting face. Backspacing is the distance (in inches) from the mounting face to the back lip of the wheel. They describe the same thing two ways: higher positive offset and more backspacing both tuck the wheel further in toward the suspension.
Formula: backspacing = (width + 1) ÷ 2 + offset ÷ 25.4. Use this wheel offset calculator when one set of wheels lists offset and another lists backspacing, then confirm fit with our wheel fitment calculator.