DNI issuing is regulated under Royal Decree 1553/2005 of 23 ?December; article 11 therein states that said document includes the personal national identification number and a checksum letter corresponding to the tax identification number.
Tax identification numbers of adult Spanish residents can be verified by calculating their checksum letter using the following algorithm:
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REMAINDER | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
LETTER | T | R | W | A | G | M | Y | F | P | D | X | B |
?
REMAINDER | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 |
---|---|---|---|---|---|---|---|---|---|---|---|
LETTER | N | J | Z | S | Q | V | H | L | C | K | E |
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For example, if the DNI number is 12345678, this, divided by 23 leaves a remainder of 14, therefore the letter is Z: 12345678Z.
Non-nationals residing in Spain have a NIE (Número de Identidad de Extranjero) which is made up of a letter (X, Y, Z), 7 numbers and a?check digit.
To calculate the check digit, each letter is replaced by a number:
and the same algorithm is used.