DNI, NIE, NIF and CIF

Spanish tax IDs have several names, and they overlap. In short: every number this library validates is a NIF, and DNI, NIE, K/L/M NIF and CIF are the kinds of NIF.

The NIF: the umbrella

The NIF (número de identificación fiscal, tax identification number) identifies every person and every entity before the Spanish tax administration. Royal Decree 1065/2007 (arts. 19 to 22) defines who gets which kind. The first character of the number tells the kinds apart, and they never overlap (NIF-1):

Kind	Who gets it	Format	Example	`type` in `validate()`
DNI	Spanish citizens	8 digits and a check letter	`12345678Z`	`"DNI"`
K/L/M NIF	People without a DNI or an NIE (see below)	K, L or M, 7 digits and a check letter	`K1234567L`	`"NIF_KLM"`
NIE	Foreign nationals	X, Y or Z, 7 digits and a check letter	`X1234567L`	`"NIE"`
CIF	Companies and other entities	An organisation key, 7 digits and a control character (a digit or a letter)	`B12345674`	`"CIF"`

import { getNifType } from "nif-dni-nie-cif-validation";

getNifType("12345678Z"); // "DNI"
getNifType("K1234567L"); // "NIF_KLM"
getNifType("X1234567L"); // "NIE"
getNifType("B12345674"); // "CIF"
getNifType("T1234567A"); // null: no kind of NIF starts with T

getNifType() reads the format only: getNifType("12345678A") is "DNI" even though its letter is wrong. To know whether a number is valid, use validate() or an isValid… function.

DNI: Spanish citizens

For a Spanish citizen, the NIF is the number of their DNI (documento nacional de identidad): 8 digits, leading zeros included, and an upper-case check letter computed from the number (DNI-1, DNI-2). People often write it without the leading zeros, or with dots and a hyphen; the library accepts both and returns the canonical form for you to store:

import { validate } from "nif-dni-nie-cif-validation";

validate("1234567L").normalized;      // "01234567L": the leading zero is added back
validate("12.345.678-z").normalized; // "12345678Z"

NIE: foreign nationals

Foreign nationals get an NIE (número de identidad de extranjero): X, Y or Z, 7 digits and a check letter (NIE-1). The X series came first; when it ran out, Y followed, then Z.

Until 2008, NIEs had 10 characters: an X, 8 digits and a letter. Those numbers are still valid, and their canonical form drops the zero after the X (NIE-3):

import { isValidNie, validate } from "nif-dni-nie-cif-validation";

isValidNie("X01234567L");             // true: the old 10-character form
validate("X01234567L").normalized;    // "X1234567L"
isValidNie("X11234567L");             // false: only a leading 0 can be dropped

K/L/M NIF: people without a DNI or an NIE

Some natural persons need a NIF but have neither a DNI nor an NIE. They get a NIF that starts with a letter (KLM-1):

K: Spaniards under 14 living in Spain who don’t have a DNI.
L: Spaniards living abroad who don’t have a DNI.
M: foreign nationals who don’t have an NIE (for example, while it is being issued; an M NIF can be temporary).

They are people, not companies. isValidDni() and isValidNaturalPersonNif() accept them, and validate() reports them as "NIF_KLM":

import { isValidCif, isValidDni, validate } from "nif-dni-nie-cif-validation";

isValidDni("K1234567L");      // true
isValidCif("K1234567L");      // false: K is not an organisation key
validate("M1234567L").type;   // "NIF_KLM"

CIF: companies and other entities

Companies, associations, public bodies and other entities have a NIF that starts with an organisation key, a letter that says what kind of entity it is, followed by 7 digits and a control character (CIF-1, CIF-2).

Until 2008 this number was called the CIF (código de identificación fiscal). Orden EHA/451/2008 renamed it: officially it is now the “NIF of a legal person or entity”. Everyone still searches for “CIF”, so the library keeps the name (isValidCif, type: "CIF"), with isValidLegalEntityNif as an alias.

import { describeCifOrganisation, validate } from "nif-dni-nie-cif-validation";

validate("B12345674").meta;   // { orgKey: "B", orgDescription: "Limited liability company" }
describeCifOrganisation("G"); // "Association"

These are the 17 organisation keys, with the name the library gives each one in the language of this page, and the kind of control character each key takes (CIF-3):

The organisation keys of a CIF, the kind of organisation each one stands for, and the kind of control character it takes
Key	Organisation	Control character
`A`	Public limited company	a digit
`B`	Limited liability company	a digit
`C`	General partnership	a digit
`D`	Limited partnership	a digit
`E`	Community of property, estate in abeyance or other entity without legal personality not covered by another key	a digit
`F`	Cooperative society	a digit
`G`	Association	a digit
`H`	Community of owners under a horizontal property regime	a digit
`J`	Civil partnership	a digit
`N`	Foreign entity	a letter
`P`	Local authority	a letter
`Q`	Public body	a letter
`R`	Religious congregation or institution	a letter
`S`	Body of the State administration or of an autonomous community	a letter
`U`	Temporary joint venture	a digit
`V`	Other type not covered by another key	a digit
`W`	Permanent establishment of an entity not resident in Spain	a letter

The 7 digits are random since 2008: they no longer say anything about the province, so the library doesn’t check province codes (CIF-5).

VAT numbers

A Spanish VAT number, used for intra-EU trade, is ES followed by the NIF (VAT-1). isValidSpanishVat() checks that format; validate() accepts the prefix only when you ask for it:

import { isValidSpanishVat, validate } from "nif-dni-nie-cif-validation";

isValidSpanishVat("ES12345678Z");                               // true
validate("ES12345678Z").error?.code;                            // "INVALID_FORMAT"
validate("ES12345678Z", { allowVatPrefix: true }).normalized;   // "12345678Z"

Not a NIF

Some rules you will find online have no official source, and the library doesn’t apply them. A number starting with T is not a NIF, a CIF starting with 00 doesn’t need a letter, and the CIF digits carry no province code. The FAQ explains each one, and the official sources list them.