Postal Code Search

Korea introduced a 5-digit postal code system in August 2015 alongside the nationwide rollout of road-name addresses. The old 6-digit lot-based postal codes were discontinued — each road-name address is assigned a unique 5-digit code. Always use the new 5-digit code on forms and parcels.

Before August 2015, Korea's 6-digit postal codes were assigned by dong/ri administrative unit, so a wide area could share a single code. The new 2015 system is based on individual road segments instead, so different roads within the same neighborhood get different 5-digit codes. This makes delivery areas far more precise and improves automated mail-sorting accuracy. The old 6-digit codes were officially discontinued on August 1, 2015 and are no longer valid — copying one from an old document or business card can cause misdelivery.

Underlying the new postal system is a concept called the national basic district — a set of base units the land is divided into, sized with population and road networks in mind so they can serve postal, statistical, and administrative purposes alike, independent of cadastral administrative boundaries. In a 5-digit postal code, the first 3 digits represent this national basic district, and the last 2 represent a finer delivery unit within it (a road name or adjoining segment). It's a general-purpose land-division framework designed to support not just postal codes but future everyday statistics and emergency-location reporting as well.

If your search isn't returning results, check these three things.

1. Check the input unit. A city/county/district name alone cannot be searched (e.g. entering just "Seoul" fails). Enter a road name + building number (e.g. Sejong-daero 110) or a dong/ri + lot number.
2. Try adjusting spacing. Adding or removing the space between the road name and building number can sometimes change the results.
3. Try a building or complex name. A partial apartment complex or building name often works too, which helps when you don't know the exact road name.

This tool calls the Ministry of the Interior and Safety road-name address API (juso.go.kr) in real time — it is not a locally stored or processed dataset. Searches may be temporarily unavailable during API maintenance; in that case, check directly at the Juso address system (juso.go.kr).