What are the two Brazilian plate formats?

The old format (pre-2018) is three letters and four digits, e.g. ABC-1234. The Mercosul format (2018 onward) is three letters, a digit, a letter, then two digits, e.g. ABC1D23. Both have exactly seven characters.

How does the conversion between formats work?

The Mercosul plate is a one-to-one conversion of the old plate. The fifth character — the second of the four digits in the old plate — is replaced by a letter A to J using the map 0 to A, 1 to B, and so on up to 9 to J. Everything else stays the same.

Does the plate encode the state?

Historically yes. DENATRAN allocated contiguous three-letter prefix ranges to each state, so the prefix indicates the issuing state. The validator shows an approximate state range, but ranges overlap and the mapping is not exact.

Does a valid format confirm registration?

No. This is a format validator. To confirm a plate belongs to a registered vehicle you must query the official DETRAN or DENATRAN systems for that state.

Why does my Mercosul plate fail?

The most common cause is the fifth character not being a letter A to J. Only those ten letters are produced by converting a digit, so any other letter in that position is invalid.

Brazil Vehicle Plate Validator

A Brazilian vehicle plate (placa) comes in two forms: the old ABC-1234 layout and the Mercosul ABC1D23 layout that replaced it from 2018. Because the Mercosul plate is a direct conversion of the old one, this free validator checks either format and shows you the equivalent in the other. It is built for Brazilian logistics and vehicle workflows.

How it works

Both formats have exactly 7 characters. The tool normalises the input (uppercased, hyphen removed) and tests two patterns:

Old format: LLLNNNN — 3 letters + 4 digits (ABC-1234).
Mercosul format: LLLNLNN — 3 letters, 1 digit, 1 letter, 2 digits (ABC1D23).

The conversion rule is fixed: the 5th character (the 2nd of the four digits in the old plate, a digit 0–9) maps to a letter using 0→A, 1→B, 2→C, … 9→J. So the Mercosul 5th character must be one of A–J; the tool rejects any other letter there. It also shows the approximate issuing state from the three-letter prefix range.

Example

Convert the old plate ABC-1234 (characters A B C 1 2 3 4):

5th character = 2  ->  letter C
Mercosul equivalent = ABC1C34

Entering ABC1C34 converts straight back to ABC-1234.

Notes

A valid result confirms the plate matches one of the two official formats and shows the conversion and an approximate state. The state ranges allocated by DENATRAN overlap and are not exact, so treat the state as indicative. A valid format does not confirm registration — query DETRAN/DENATRAN for that. All processing is local; nothing is sent anywhere.