Japan Postal Code Search

A free tool to instantly search over 120,000 Japanese postal codes by postal code or address. Supports CSV export and one-click copying of postal codes.

Tips

  • You can search a postal code with or without a hyphen, like "123-4567". Just enter the digits and matching results are narrowed down automatically.
  • You can also search using just part of an address. Enter a municipality or town name in kanji or kana to instantly see the matching postal codes.
  • Search results can be exported to CSV with one click, so you can use them directly for mailing labels or address books.
  • You can also enter the old 5-digit postal code used before 1998 to check how it corresponds to the current 7-digit postal code.
  • Clicking a postal code in the results automatically copies it to your clipboard, speeding up data entry into other forms.

Frequently Asked Questions

On February 2, 1998, postal codes were expanded from 5 digits to the current 7 digits. The first 3 digits represent the region, and the last 4 digits represent the town area or large-volume mail recipients.

Large housing complexes, apartment buildings, or major businesses are sometimes assigned their own individual postal code as a single "building," which is why a single town area can have multiple postal codes.

A postal code can identify the prefecture, municipality, and town area, but not the specific house number or building name. Accurate delivery requires that additional information as well.

Japan Post updates its postal code data around the end of each month, and this tool automatically updates to match that latest data.

P.O. boxes and businesses that handle large volumes of mail are individually assigned their own dedicated 7-digit postal code, separate from the postal code assigned to the surrounding town area.
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Side Note — The History and Structure of Japanese Postal Codes

Japan introduced its postal code system in 1968. Initially consisting of 3 or 5 digits, it was introduced to make mechanical (automated) mail sorting more efficient. The starting point of the system was "coding" addresses to mechanize sorting work that had previously been done by hand, and its main purpose was to improve postal sorting efficiency internally — quite unrelated to the kind of online address lookup we use today.

On February 2, 1998, the codes were expanded to the current 7 digits. This allowed postal codes, which previously could only specify down to the municipality level, to identify addresses down to the individual town area, greatly improving sorting accuracy. The first two digits represent the prefecture, followed by digits that hierarchically represent the municipality and town area. This 7-digit expansion made it possible to reverse-lookup an address from a postal code almost uniquely, which is what makes address search services like this one possible today.

Looking abroad, the United States ZIP code uses 5 digits (9 digits in its extended form), while the United Kingdom postcode uses a distinctive variable-length format combining letters and numbers. The UK system in particular is so fine-grained that a single postcode often covers only a handful of buildings, giving it even higher resolution than Japan's 7-digit postal code. These differing designs reflect each country's differences in land area and address-naming conventions.