# Postal Code Search

> Search addresses and look up Korean postal codes (zip codes).

## What is Postal Code Search?

Postal Code Search is a service that uses the Kakao (Daum) Postcode API to quickly search for road-name addresses, land-lot addresses, and English addresses across South Korea, and find the corresponding 5-digit postal code (zip code). South Korea's postal code system was completely reformed from a 6-digit to a 5-digit system on August 1, 2015. The new 5-digit postal codes divide the country into approximately 37,000 zones, designed around the road-name address system for more precise location identification. Under the old 6-digit system, all addresses within the same administrative dong shared the same postal code, but the 5-digit system can assign different codes even within the same dong based on road names and building numbers. This service supports various search terms including road-name addresses, land-lot addresses, building names, and apartment complex names. For example, you can search for 'Teheran-ro 152', 'Samseong-dong 159', or 'Gangnam Finance Center'. Search results display both road-name and land-lot addresses simultaneously, making it easy to see the correspondence between the two address systems. English addresses are also provided, which is useful for international shipping or preparing documents in English. Postal codes are essential in many everyday situations: online shopping, parcel delivery, government paperwork, banking address registration, real estate transactions, and move-in notifications. Since the Road Name Address Act mandated the use of road-name addresses in most public and financial institutions, accurately confirming your road-name address and postal code has become increasingly important.

## How to Use Postal Code Search

Using this service is very intuitive. When you access the page, the Kakao postal code search widget is automatically displayed. Simply type the address you want to find in the search bar.

The search supports various formats. You can search by road name (e.g., 'Sejong-daero 209', 'Teheran-ro 152'). You can also search by dong/eup/myeon name (e.g., 'Samseong-dong', 'Yeoksam-dong 700'). Building names and apartment complex names also work (e.g., 'Gangnam Finance Center', 'Raemian', 'Hillstate'). Including the si/gun/gu name provides more accurate results (e.g., 'Gangnam-gu Yeoksam-dong').

When you click on the desired address from the search results, detailed information appears in a card format. The card includes the postal code (5 digits), road-name address, land-lot address, English address, and building name. Click the 'Copy' button next to any field to instantly copy it to your clipboard for pasting elsewhere.

You can search multiple addresses in succession. After selecting your first address, press the 'Search New Address' button to bring back the search widget. Previous results remain displayed below, making it convenient to compare or verify postal codes for multiple addresses at once.

Search tips: For precise results, include the si/gun/gu name when possible. For apartments, just the complex name usually works. Including the lot number provides more accurate results. If you need an English address, you can find and copy it directly from the result card without needing a separate translation service.

## South Korea's Postal Code System

South Korea's postal code system has undergone several reforms since its initial introduction in 1970.

[History of Postal Codes]
• 1970: First 5-digit postal codes introduced (Seoul 100-00 format)
• 1988: Reformed to 6-digit codes (XXX-XXX format, ~2,800 zones nationwide)
• August 1, 2015: New 5-digit postal codes launched (XXXXX format, ~37,000 zones)
• 2021: Old 6-digit postal codes fully discontinued

[5-Digit Postal Code Structure]
The new postal codes consist of 5 digits (00000–99999), where the first 2–3 digits indicate the region.
• 01–09: Seoul
• 10–18: Gyeonggi-do
• 21–23: Incheon
• 24–26: Gangwon-do
• 27–29: Chungcheongbuk-do
• 30–32: Sejong, Daejeon
• 33–36: Chungcheongnam-do
• 37–40: Gyeongsangbuk-do
• 41–44: Daegu
• 45–48: Gyeongsangnam-do
• 49–52: Ulsan, Busan
• 53–56: Jeollabuk-do
• 57–60: Jeollanam-do, Gwangju
• 61–63: Jeju

The remaining 2–3 digits represent specific delivery zones within each region. The 5-digit system is designed around the road-name address system, assigning the same postal code to consecutive building numbers on the same road. This has significantly improved the efficiency of automated mail sorting.

[Road-Name vs. Land-Lot Addresses]
Road-name addresses follow the 'road name + building number' format (e.g., 110, Sejong-daero), while land-lot addresses use the 'dong/ri + lot number' format (e.g., 77-6, Sejong-ro). Road-name addresses have been the legal standard since January 1, 2014. This service allows you to check both address formats simultaneously.

## Tips for Using Postal Code Search

Here are some tips to help you make the most of the postal code search service.

First, use it when entering delivery addresses for online shopping. Most shopping sites require a postal code and road-name address. Search here, then use the copy button for quick entry.

Second, use the English address for international shipping or English documents. Since the English address is automatically displayed in search results, you don't need to visit a separate address translation website. It's ready to use for international shopping sites, English resumes, and overseas document submissions.

Third, if you're planning a move, look up the postal code for your new address in advance. You'll need it for residence registration, bank address changes, and updating various subscription services.

Fourth, confirming the recipient's exact postal code when sending parcels can reduce delivery errors. This is especially important for large apartment complexes or mixed-use buildings where specifying the building and unit number matters.

Fifth, for tasks requiring multiple address lookups (bulk mailings, customer address verification, etc.), take advantage of the sequential search feature. Results accumulate on the page, making it easy to compare postal codes for multiple addresses at a glance.

Sixth, including the si/gun/gu name in your search prevents confusion from identically-named dongs. For example, 'Sinsa-dong' exists in both Gangnam-gu and Eunpyeong-gu in Seoul, so searching 'Gangnam-gu Sinsa-dong' gives you the right result.

Seventh, if searching by building name doesn't work, try the road name or dong name instead. Recently completed buildings may take some time to appear in the database.

Eighth, postal codes can change due to regional boundary changes, new housing developments, or administrative redistricting. When filling out important documents, it's good practice to verify the current postal code.

## Frequently Asked Questions

### Q. Why did Korea change from 6-digit to 5-digit postal codes?

The old 6-digit postal code system, introduced in 1988, divided the country into only about 2,800 zones. This meant that large areas shared the same postal code, resulting in low precision for mail sorting and delivery. The 5-digit system introduced in 2015 subdivides the country into approximately 37,000 zones, greatly improving automated mail sorting efficiency. It is also integrated with the road-name address system, making it possible to determine the exact postal code from just the road name and building number. The old 6-digit codes were fully discontinued in 2021, and only the 5-digit codes are now in use.

### Q. What's the difference between road-name and land-lot addresses?

Land-lot addresses (jibun-juso) use the 'dong/ri + lot number' format (e.g., 31, Taepyeong-ro 1-ga, Jung-gu, Seoul), based on land parcel numbers. Road-name addresses (doromyeong-juso) use the 'road name + building number' format (e.g., 110, Sejong-daero, Jung-gu, Seoul), assigning names to roads and numbers to buildings. Road-name addresses have been the legal standard since January 1, 2014, and their use is mandatory in public institutions and financial organizations. However, land-lot addresses still appear in some documents like property registration records. It's helpful to know both systems. This service displays both address types simultaneously for your convenience.

### Q. What format is the English address in?

The English address is a romanized version of the road-name address, used for international mail and English-language documents. The order is reversed from Korean addresses, going from the smallest to the largest unit. For example, '서울특별시 강남구 테헤란로 152' becomes '152, Teheran-ro, Gangnam-gu, Seoul, Korea' in English. Dong names and building names are transliterated from Korean pronunciation into Roman letters. For international mail addressed to Korea, add 'Republic of Korea' or 'South Korea' and the postal code at the end of the English address. This service automatically displays the English address in search results, so you can copy and use it directly without any separate translation step.

### Q. Can the same building have different postal codes?

Yes, this is possible. In the 5-digit postal code system, codes are assigned by road. If a large building faces multiple roads, it may have different postal codes depending on which entrance (and therefore which road name) is used. Additionally, within a single large complex (such as a large apartment complex or university campus), different buildings may receive different postal codes based on their location. In such cases, entering the specific building or dong number during the search will help find the correct code. To avoid issues with parcel or mail delivery, use the postal code corresponding to the road-name address of the actual entrance you use.

### Q. What should I do if I can't find an address?

There are several common reasons an address might not appear, along with solutions. First, for newly constructed buildings, it may take time for the address to be registered in the database. In this case, search for the road name where the building is located to find nearby addresses. Second, the search term might be too specific or contain a typo. Try searching with just the si/gun/gu and dong name first, then look through the results. Third, there may have been administrative boundary changes or road name changes. Try searching with the new address instead of the old one. Fourth, the building name might differ from its officially registered name. Try searching by road name and building number instead. If you still can't find the address, you can check with the Korea Post customer service center (1588-1300) or the Address Information Portal (juso.go.kr).