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DNI / NIE Letter Calculator — Validate Spanish NIF and NIE

Calculate the control letter of a Spanish DNI or NIE and validate full numbers: 12345678 → 12345678Z, X1234567 → X1234567L. Paste up to 500 numbers, one per line.

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Enter 8 digits to get the letter, or a full DNI/NIE to check it. The check verifies the control letter only, not that the document exists.

Up to 100,000 UTF-16 units per input and 1,000,000 per result. See the supported formats and examples below.

Result

Add your input or load an example, then run the tool. Your result will appear here.

How to use

  1. Paste DNI or NIE numbers, one per line — with or without the letter.
  2. Run the calculation.
  3. Numbers without a letter get it added; complete numbers are marked valid or show the expected letter.

Example

12345678 → 12345678Z
X1234567L → ✓ NIE
12345678A → ✗ expected letter Z

Details and limitations

The letter is the remainder of the number divided by 23, looked up in TRWAGMYFPDXBNJZSQVHLCKE. For an NIE, X, Y and Z count as 0, 1 and 2 before dividing.

Numbers are personal data: they stay in your browser and are not sent anywhere.

FAQ

How is the DNI letter calculated?

Divide the 8-digit number by 23 and take the remainder (0–22). The letter at that position in TRWAGMYFPDXBNJZSQVHLCKE is the control letter: 12345678 leaves 14, which is Z.

Does it work for NIE numbers?

Yes. Replace X with 0, Y with 1 and Z with 2, then apply the same calculation: X1234567 gets the letter L.

Does a correct letter mean the DNI is real?

No. It only shows the number is internally consistent; it does not check any register.

Format references

Tool page updated: