Japan
How to Find a Japan Postal Code
How to look up the seven-digit postal code for a Japanese address using Japan Post's own directory, and how to verify and handle uncertain results.
Updated 14 October 2026 · 3 min read
Japan Post maintains the official postal code data, and its own address-to-code search is the authoritative way to find a code. You search by prefecture, city or ward and district, and the tool returns the seven-digit code.
Ways to find the code
- Japan Post's search tool. Enter the prefecture, city and district. Results list the postal code for that area. Searching from the code returns the area name, which is a good reverse check.
- Mail and documents. Envelopes, utility bills, delivery slips and registration cards display the code.
- The recipient or building management. For apartments and offices, the building's management can supply the exact code.
- Local post office. Staff can confirm the code for a district or building.
How to verify
Check that you have seven digits in the pattern NNN-NNNN. Search from the code as well, and check that the prefecture, city and district shown agree with your address. Because some districts contain multiple codes, depending on block numbers, make sure the result applies to your block. Companies and large buildings may be listed individually, and should use that code on business mail.
If you are unsure
- Use the code from previous mail whenever it exists.
- If a district has several codes, use the one whose block range includes your number.
- Write the building name and room number clearly, because they identify the delivery point even when the code is slightly off.
- Avoid guessing digits; a valid-looking but wrong code can delay delivery.
Mail for a business or a large facility sometimes has its own dedicated code, so check whether the organisation prints one on its letterhead before falling back on the district code.
Adding an exact location
The postal code defines the area, and the block numbers define the building lot. For a building with several entrances, a rear delivery door or a rural property, you can add a UPCS code. Use the UPCS map, mark the exact spot and copy the JP-XXXX-XXXX code. It is not an official postal code and does not replace one.
For the order of the other address components, see how to write a Japan address, and for the number format, the Japan postal code format.
Frequently asked questions
Where can I find the official Japan postal code list?
Japan Post, the national postal operator, publishes the official postal code data and provides a search tool by address.
Do large buildings have their own postal code in Japan?
Some large buildings, companies and organisations have an individual code. Check the one on their mail or in the directory.