Regex for Japanese Postal Code (郵便番号)

Regex for Japanese Postal Codes

Japanese postal codes (郵便番号) are seven digits, normally formatted as three digits, a hyphen, then four digits. They can appear with or without the hyphen, and historic forms include the postal mark 〒.

Standard Pattern (with hyphen)

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

Matches 100-0001 (Chiyoda-ku, Tokyo).

With or Without Hyphen

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

Matches 100-0001 and 1000001.

With Optional 〒 Prefix and Hyphen

^〒?\d{3}-?\d{4}$

Matches 〒100-0001, 100-0001, 1000001.

Allow Full-Width Digits and Hyphen

Japanese forms commonly accept full-width characters:

^〒?[0-9０-９]{3}[-－ー‐]?[0-9０-９]{4}$

Matches １００－０００１ and 100ー0001.

Tested Examples

Input	Standard	Flexible
100-0001	yes	yes
1000001	no	yes
〒100-0001	no	yes (with prefix variant)
１００－０００１	no	yes
10-00001	no	no
100-001	no	no (only 6 digits total)

Normalizing Before Storage

Strip the prefix and hyphen before storing to keep entries consistent:

input
  .replace(/[０-９]/g, c => String.fromCharCode(c.charCodeAt(0) - 0xfee0))
  .replace(/[〒\-－ー‐]/g, "")

Note on Real-World Validation

Regex confirms format only. To verify a code maps to a real address, query the Japan Post CSV (KEN_ALL.csv) or a paid address API.