BR License Plate Generator

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Mercosul plate format: LLLNLNN explained

convert legacy plate to Mercosul

How a legacy plate becomes Mercosul

When a vehicle with a legacy-standard plate migrates to the Mercosul spelling, only one character changes: the second digit becomes the letter at that same position in the alphabet.

The conversion rule, digit to letter

The legacy plate is LLLNNNN (3 letters + 4 digits). In the official Mercosul conversion, positions 1, 2, 3, 4, 6 and 7 stay exactly the same; only position 5 (the old second digit) changes, becoming the letter at the matching position in the alphabet: 0 becomes A, 1 becomes B, 2 becomes C, and so on up to 9 becoming J.
Since only the letters A through J are used in this specific conversion (because only digits 0 through 9 exist), a plate freshly converted from the legacy standard is recognizable: its 5th position will always be one of the first ten letters of the alphabet, even though brand-new Mercosul plates can use any of the 26 letters there.

Conversion examples

Simple conversion

Input: ABC-1234
Expected output: ABC1C34

The second digit (2) became the letter C (3rd letter of the alphabet, index 2).

Conversion with digit 9

Input: ABC-1934
Expected output: ABC1J34

The highest possible digit (9) becomes the letter J, the ceiling of this conversion range.

Full tool FAQ

Is the generated plate from a real vehicle?

No. It is a synthetic alphanumeric combination, generated locally, that follows the correct format but does not correspond to any registered vehicle. The tool never queries DETRAN or any real database.

What is the difference between the Mercosul and the legacy plate?

Does a plate have a check digit like a CPF?

How does a legacy plate become Mercosul during migration?

Can I use the generated plate on a real document or vehicle listing?

Does the tool check DETRAN to see if the plate exists?

Why can a 7-character plate be rejected as invalid?

Can any letter of the alphabet appear on a plate?

Frequently asked questions

Does every legacy plate need to be converted to Mercosul?

Not necessarily. Legacy-standard plates remain valid for vehicles that already carry them; conversion typically happens at ownership transfer, plate reissue, or by the owner's choice.

Why does only the 5th position change during conversion?

Because CONTRAN's specification designed the transition to preserve as much visual continuity with the old plate as possible, swapping only the character needed to tell the two standards apart.

Can I test this conversion with a synthetic plate?

Yes, generate a legacy-standard plate in the tool above and apply the same rule (2nd digit becomes a letter by alphabet position) to see the equivalent Mercosul version.

Next steps

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convert legacy plate to Mercosul

How a legacy plate becomes Mercosul

When a vehicle with a legacy-standard plate migrates to the Mercosul spelling, only one character changes: the second digit becomes the letter at that same position in the alphabet.

The conversion rule, digit to letter

The legacy plate is LLLNNNN (3 letters + 4 digits). In the official Mercosul conversion, positions 1, 2, 3, 4, 6 and 7 stay exactly the same; only position 5 (the old second digit) changes, becoming the letter at the matching position in the alphabet: 0 becomes A, 1 becomes B, 2 becomes C, and so on up to 9 becoming J.

Since only the letters A through J are used in this specific conversion (because only digits 0 through 9 exist), a plate freshly converted from the legacy standard is recognizable: its 5th position will always be one of the first ten letters of the alphabet, even though brand-new Mercosul plates can use any of the 26 letters there.

Full tool FAQ

Is the generated plate from a real vehicle?

What is the difference between the Mercosul and the legacy plate?

Does a plate have a check digit like a CPF?

How does a legacy plate become Mercosul during migration?

Can I use the generated plate on a real document or vehicle listing?

Does the tool check DETRAN to see if the plate exists?

Why can a 7-character plate be rejected as invalid?

Can any letter of the alphabet appear on a plate?

Frequently asked questions

Does every legacy plate need to be converted to Mercosul?

Not necessarily. Legacy-standard plates remain valid for vehicles that already carry them; conversion typically happens at ownership transfer, plate reissue, or by the owner's choice.

Why does only the 5th position change during conversion?

Because CONTRAN's specification designed the transition to preserve as much visual continuity with the old plate as possible, swapping only the character needed to tell the two standards apart.

Can I test this conversion with a synthetic plate?

Yes, generate a legacy-standard plate in the tool above and apply the same rule (2nd digit becomes a letter by alphabet position) to see the equivalent Mercosul version.