Identify · owner & restorer reference
Where the numbers hide.
A Jeep does not carry one identifier in one place. The format, the location, and even the number of stampings changed with every ownership era. Read the era first, then the number — and remember that a frame and a body tub that disagree are themselves evidence.
WWII military · MB & GPW
Two identity plates carry the same serial: one on the left front chassis frame rail, one on the firewall under the hood. A separate body-tub number is stamped in the left toe-board gusset. On a genuine wartime Jeep these can disagree after decades of rebuilds — which tells you the vehicle's history rather than invalidating it. The earliest MBs also wore the maker's name in script on the rear panel.
Willys & Kaiser · 1945–1970
Civilian serials grew structured: a first character for the basic model, a body-type letter, and codes for cylinder count, model year, and series-within-year. Plates lived on the firewall and frame. Because a swapped body or frame is common on working farm and ranch Jeeps, cross-checking both locations is the first authentication step.
AMC / Jeep Corporation · 1971–1980
A 13-character VIN: manufacturer (J), a single model-year digit, a plant/drivetrain code, a two-character series (CJ-5, CJ-7, Wagoneer, Cherokee SJ …), a GVW class, an engine code, and a sequence. A separate data plate near the master cylinder carries limited paint and interior trim codes — the closest this era has to a Mustang-style fender tag. Do not run a modern check-digit test on it; the check digit did not exist yet.
Standardized VIN · 1981–present
The 17-character ISO 3779 / NHTSA standard, readable on the driver-side dash and the door-jamb certification label. It adds a manufacturer identifier, a calculated check digit in position 9, a model-year letter that repeats every 30 years (resolved by position 7), an assembly-plant code, and a sequence. A modern build sheet and window sticker (Monroney label) are separate documents — one internal, one consumer-facing.
What a decode is — and is not
Reading the characters tells you what the tag claims. It is labelled decoded: a rule-based interpretation, never proof of authenticity, never "matching numbers", never a factory certificate. Physical inspection, factory records, and marque-specialist registries outrank a decode every time. JeepFacts does not certify authenticity, ownership, or value.
Read yours
The VIN & serial reader detects which era your identifier belongs to and explains every position — entirely in your browser, with nothing uploaded or logged. For the deeper era-by-era research, see the methodology and the coverage ledger.