Pattern

Regex for Japanese postal code

7-digit Japanese postal code, formatted NNN-NNNN.

The Japanese postal code regex is ^\d{3}-\d{4}$ — copy it below, or open it in the explainer for a token-by-token breakdown.

The pattern

^\d{3}-\d{4}$

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What it matches

100-0001
530-0001
810-0001

What it doesn't match

1000001
100-001
ABCDEFG

Notes & gotchas

Format: 3 digits + hyphen + 4 digits. The first 3 digits indicate the region; the last 4 narrow down to the area.

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{3}`	exactly 3 times: digit (0–9)
`-`	literal text “-”
`\d{4}`	exactly 4 times: digit (0–9)
`$`	end of string (or line in multiline mode)

About this pattern

Country-specific identifier formats vary widely. The pattern below validates structure; many real IDs include checksums that regex can't verify alone.

Quick usage in different languages

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

JavaScript: /^\d{3}-\d{4}$/.test(value)
Python: re.match(r"^\d{3}-\d{4}$", value)
Java: Pattern.compile("^\\d{3}-\\d{4}$").matcher(value).matches()
C# / .NET: Regex.IsMatch(value, @"^\d{3}-\d{4}$")
Go: regexp.MustCompile(`^\d{3}-\d{4}$`).MatchString(value)
Ruby: /^\d{3}-\d{4}$/.match?(value)
PHP: preg_match('~^\d{3}-\d{4}$~', $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.
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 japanese postal code against a source of truth (database, API, or checksum) where it matters.

Related patterns

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