How to use: Spanish DNI and NIE letter calculator
- Type the 8 digits of the DNI, or the X, Y or Z plus the 7 digits of the NIE.
- See the matching letter and the full number.
- If you also type the letter, it tells you whether it matches the number.
What it accepts and what you get
- Input
- A DNI number (8 digits) or NIE number (X, Y or Z + 7 digits), with or without the letter.
- Output
- The control letter, the full number and, if you typed the letter, whether it is correct.
- Where your data is processed
- Your data is processed in your browser and is not sent to our servers.
Limitations and notes
- It uses the official formula: the number (with X=0, Y=1, Z=2 for NIEs) divided by 23 gives the remainder that picks the letter.
- It only checks that the number-letter pair is consistent. It does not confirm the document exists, is valid or belongs to anyone.
- K, L, M letters and company CIFs are not supported. No random numbers are generated either.
Frequently asked questions
Is the number I type stored?
No. It is calculated in your browser and neither sent nor stored.
Can I use it to check a DNI is real?
No: it only catches a mistyped letter. An invented number with the right letter would also pass.
When to use it
- When filling in a form and unsure about the letter.
- To spot a wrongly copied letter in a data list.
- To understand how the letter is calculated.
Examples
- 12345678
- The letter is Z, so it becomes 12345678Z.
- X1234567
- The X counts as 0, and the letter turns out to be L.
Common mistakes
- Believing a matching pair proves the document is real.
- Forgetting the leading zero on short numbers.
- Using the calculator with company CIFs.