Regex for Dutch postal code
NNNN AA format Dutch postal.
The Dutch postal code regex is ^\d{4}\s?[A-Z]{2}$ — copy it below, or open it in the explainer for a token-by-token breakdown.
The pattern
^\d{4}\s?[A-Z]{2}$
What it matches
1011 AB1234CD9999 XX
What it doesn't match
1011A1234 ABCABCD 12
Notes & gotchas
Dutch postal codes: 4 digits + optional space + 2 letters. Distinctive among European postcodes for the letter pair.
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.
Open in explainer →Token-by-token breakdown
Every part of the pattern, left to right:
| Token | Meaning |
|---|---|
^ | start of string (or line in multiline mode) |
\d{4} | exactly 4 times: digit (0–9) |
\s? | optional (zero or one): whitespace |
[A-Z]{2} | exactly 2 times: 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{4}\s?[A-Z]{2}$/.test(value) - Python:
re.match(r"^\d{4}\s?[A-Z]{2}$", value) - Java:
Pattern.compile("^\\d{4}\\s?[A-Z]{2}$").matcher(value).matches() - C# / .NET:
Regex.IsMatch(value, @"^\d{4}\s?[A-Z]{2}$") - Go:
regexp.MustCompile(`^\d{4}\s?[A-Z]{2}$`).MatchString(value) - Ruby:
/^\d{4}\s?[A-Z]{2}$/.match?(value) - PHP:
preg_match('~^\d{4}\s?[A-Z]{2}$~', $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 dutch postal code against a source of truth (database, API, or checksum) where it matters.
Related patterns
More patterns in the Europe 🇪🇺 category:
See also
Browse all 300 patterns in the library, or open this regex in the interactive explainer to see a token-by-token breakdown, test against custom input, and generate code in seven languages.