Japan Postal Code Format Guide
Japanese postal codes contain seven digits, conventionally split 3-4 with a hyphen and often preceded by the postal mark ใ. Addresses proceed from prefecture to municipality to smaller area.
Standard format
NNN-NNNN
Example
100-0001
Implementation and validation notes
Japanese postal codes contain seven digits, conventionally split 3-4 with a hyphen and often preceded by the postal mark ใ. Addresses proceed from prefecture to municipality to smaller area.
Validate required state, character set, length, and syntax on the client, then repeat validation on the server. Preserve the original input and normalize into a separate field; never truncate local scripts, compound names, or leading zeroes to fit a single Western assumption.
This guide describes common formats rather than an official registry and cannot enumerate every exception. Generated output is for testing only, not delivery, calling, identity verification, or real account activity.
Related resources
Frequently asked questions
What is the standard Japan postal code format?
A common representation is NNN-NNNN, for example 100-0001. Japanese postal codes contain seven digits, conventionally split 3-4 with a hyphen and often preceded by the postal mark ใ. Addresses proceed from prefecture to municipality to smaller area.
How should Japan postal code test data be stored?
Store the original value as a string so leading zeroes, spaces, hyphens, accents, and local scripts are preserved. Use a separate normalized field for search.
Does correct formatting prove the data is real?
No. Syntax validation cannot prove an address is deliverable, a number is assigned, or a name belongs to a real person.