Taiwan 郵遞區號 validator
How the 郵遞區號 format works
- Format
- 3 digits, optionally followed by 2 more digits
- Example
- 100
Things to watch for
- Format-only check — does not confirm the 郵遞區號 actually exists
- Accepts both the 3-digit zone code and the extended 3+2 digit code introduced in 1991 for finer routing
- A further optional 3+3 (6-digit) extension exists since 2020 for bulk/corporate mail, but is not covered by this validator
^[0-9]{3}([0-9]{2})?$A Taiwanese 郵遞區號 (postal area code) is the code Chunghwa Post uses to route mail, and unlike most postcodes in this comparison it doesn’t have one fixed length. A bare 3-digit zone code (e.g. 100 for Taipei’s Zhongzheng District) has been valid since the system’s early days; in 1991 the post office added an optional 2-digit suffix for finer routing, giving a 3+2 five-digit form. Anyone validating a Taiwanese shipping address, a checkout form, or a spreadsheet of customer records needs the code to match one of those two accepted lengths before it’s trusted.
Because either length is accepted, a validator here has to check the shape as a whole rather than assuming a single fixed digit count — a 4-digit or 6-digit string is invalid, but both 3 and 5 digits are correct.
How this validator works
This tool checks that the input is either exactly 3 digits, or 3 digits followed immediately by 2 more, with no letters, spaces, or hyphens, entirely in your browser, with nothing sent to a server.
What a pass doesn’t tell you
A 郵遞區號 carries no check digit, so matching one of the two accepted lengths is the most a client-side tool can confirm — not that Chunghwa Post has assigned it to a real district. Confirming that requires Chunghwa Post’s own postcode lookup.
Scope: this page and tool cover format validation only, for the 3-or-5-digit format — not the newer optional 6-digit bulk-mail extension, address lookup, or confirming a code is currently in use.
郵遞區號 FAQ
Why does Taiwan's postcode have a variable length?
The Directorate General of Posts upgraded from a bare 3-digit zone code to an extended 3+2 digit format in 1991 for finer routing, but never made the extra 2 digits mandatory for everyday mail — so both 100 and 10058 are valid depending on how much precision the sender includes.
Is there now also a 6-digit Taiwanese postcode?
Yes — a further optional 3+3 six-digit extension was introduced in March 2020, mainly for corporate and bulk-mail customers. Everyday correspondence still commonly uses the 3-or-5-digit format this validator checks, which the 6-digit code isn't.
Does a correctly formatted 郵遞區號 mean it actually exists?
No. This tool only confirms the string matches the 3-or-5-digit shape — it doesn't check it against Chunghwa Post's actual assignment list. Confirming a code is real, and seeing which district it names, requires Chunghwa Post's own postcode lookup.