Pattern

Regex for Spanish DNI

Spanish national ID — 8 digits + check letter.

The Spanish DNI regex is ^\d{8}[A-Z]$ — copy it below, or open it in the explainer for a token-by-token breakdown.

The pattern

^\d{8}[A-Z]$

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What it matches

12345678Z
98765432B

What it doesn't match

1234567Z
12345678
12345678AA

Notes & gotchas

Documento Nacional de Identidad (DNI): 8 digits followed by 1 check letter. The letter is derived from the digits modulo 23 against a fixed alphabet (TRWAGMYFPDXBNJZSQVHLCKE).

Code in your language

Use the explainer's Code tab to generate ready-to-paste snippets in JavaScript, Python, Java, .NET, Go, Ruby, and PHP for this pattern.

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Token-by-token breakdown

Every part of the pattern, left to right:

Token	Meaning
`^`	start of string (or line in multiline mode)
`\d{8}`	exactly 8 times: digit (0–9)
`[A-Z]`	any of: uppercase letters
`$`	end of string (or line in multiline mode)

About this pattern

European Union identifiers follow standards set by individual member states with EU-wide coordination (VAT VIES, IBAN/SEPA, etc.). The regex validates structure; for production use, validate via the appropriate registry.

Quick usage in different languages

This exact pattern — with the correct escaping and idioms for each language:

JavaScript: /^\d{8}[A-Z]$/.test(value)
Python: re.match(r"^\d{8}[A-Z]$", value)
Java: Pattern.compile("^\\d{8}[A-Z]$").matcher(value).matches()
C# / .NET: Regex.IsMatch(value, @"^\d{8}[A-Z]$")
Go: regexp.MustCompile(`^\d{8}[A-Z]$`).MatchString(value)
Ruby: /^\d{8}[A-Z]$/.match?(value)
PHP: preg_match('~^\d{8}[A-Z]$~', $value)

The explainer’s Code tab regenerates these for any pattern you paste, and the downloadable cheat sheet bundles the breakdown, all seven snippets, and the pitfalls below onto one printable page.

Common pitfalls

Anchored to the whole string. This pattern uses ^ and $, so it requires the entire input to match. To find it inside a longer text, drop the anchors and use the global (g) flag.
Uppercase only. Ranges like [A-Z] won't match lowercase. Add a-z (or the i flag) if lowercase input should be accepted.
Escape it correctly per language. In Java and JavaScript strings each backslash must be doubled (\\d); in Python, Go, and C# use raw/verbatim strings so the backslashes survive.
Validate beyond format. Matching the format doesn't guarantee the value is real. Confirm the spanish dni against a source of truth (database, API, or checksum) where it matters.

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