Project JDM Tools
Offset & Backspacing
Convert between wheel offset and backspacing instantly. Know exactly where your wheels sit before you buy.
BACKSPACING CALC
Width + offset → backspacing
Backspacing
—inches
OFFSET CALC
Width + backspacing → offset
Offset
—mm
Positive Offset
Mounting surface toward outside. Common on modern & FWD vehicles. Wheels sit further in.
Zero Offset
Mounting surface sits exactly at the wheel centerline.
Negative Offset
Mounting surface inward. Pushes wheel out for wide aggressive stance.
