South Korea 우편번호 validator
How the 우편번호 format works
- Format
- 5 digits
- Example
- 03187
Things to watch for
- Format-only check — does not confirm the 우편번호 actually exists
- Always exactly 5 digits with no separators
- Replaced the old 6-digit system on 1 August 2015, tied to the newer road-name address system (도로명주소)
^[0-9]{5}$A South Korean 우편번호 (postal number) is the 5-digit postcode Korea Post uses to route mail — for example 03187, within the Seoul range. The current 5-digit format only dates to 1 August 2015, when it replaced an older 6-digit system as part of Korea’s wider shift from land-lot-based addresses to the newer road-name address system (도로명주소) still in use today. Anyone validating a South Korean shipping address, a checkout form, or a spreadsheet of customer records needs the 우편번호 in the correct 5-digit shape before it’s trusted.
Because it’s a bare run of digits with no separator, a dropped or transposed digit produces a code that’s still superficially plausible, routing to an entirely different block without any obvious sign something’s wrong.
How this validator works
This tool checks that the input is exactly 5 digits with no letters, spaces, or hyphens, entirely in your browser, with nothing sent to a server.
What a pass doesn’t tell you
A 우편번호 carries no check digit, so matching the 5-digit shape is the most a client-side tool can confirm — not that Korea Post has assigned it to a real building or block. Confirming that requires Korea Post’s own postcode lookup.
Scope: this page and tool cover format validation only — not address lookup or confirming a 우편번호 is currently in use.
우편번호 FAQ
Has South Korea's postcode always been 5 digits?
No. Until 1 August 2015, Korea Post used a 6-digit system. The switch to the current 5-digit 우편번호 was tied to the country's broader move to a road-name address system (도로명주소), replacing the older land-lot-based addressing the previous postcode had been built around.
What does 우편번호 mean?
It means 'postal number' — the general Korean term for postcode, written directly before or as part of the full address on an envelope.
Does a correctly formatted 우편번호 mean it actually exists?
No. This tool only confirms the string is 5 digits — it doesn't check it against Korea Post's actual assignment list. Confirming a 우편번호 is real, and seeing which building or block it covers, requires Korea Post's own postcode lookup.