Japan Postal Code Search & Reverse Lookup (Code ⇄ Address)
Instantly search over 120,000 Japanese postal codes for free — look up an address from a postal code, or a postal code from an address. Supports CSV export and one-click copying of results.
What Is Japan Postal Code Search & Reverse Lookup?
A Japanese postal code (郵便番号) is 7 digits long: the first 3 digits identify the region and the last 4 identify the town area. This tool covers over 120,000 records and supports both directions — look up an address from a postal code, or a postal code from an address. Hyphens are optional, and you can search with only part of an address to narrow down candidates.
Keep in mind that a postal code can only pin down the prefecture, municipality, and town area — it cannot tell you the house number or building name. Large apartment complexes and major businesses are sometimes assigned their own individual postal code, so a single town area can have more than one code. The underlying data is refreshed every month to match Japan Post's official updates.
How to Look Up a Postal Code
- Enter a postal code or address Type digits to search by postal code, or type kanji/kana to search by address — both use the same input field.
- Check the results Matching addresses appear broken down into prefecture, municipality, and town area. Page through the list if there are many matches.
- Copy the value you need Click a postal code in the results to copy it to your clipboard, ready to paste into another form.
- Export the full list Download your search results as a CSV file to use directly for organizing address books or printing labels.
Tips for getting more out of it
- 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.
Ways to Use Postal Code Search
Online shopping and mail-order forms
Confirm the correct postal code before submitting a shipping address on an online store or mail-order checkout page, so the order is not delayed by a typo.
Moving and change-of-address paperwork
Look up the postal code for a new residence ahead of time so it is ready for utility transfer forms, bank address updates, and other move-related paperwork.
Preparing labels and shipments
Find the postal code for a recipient when you only know their address. A correct code lets machines sort the mail, speeding up delivery.
Checking address-autofill forms
Many websites auto-fill an address from a postal code. Verify in advance whether the expected address actually comes up.
Cleaning up a customer or mailing list
Bring missing or outdated postal codes up to date in bulk, then export the corrected list as CSV.
Postal Code Terms
- Postal code (郵便番号, yūbin bangō)
- A numeric code representing an address. Japan has used the current 7-digit format since 1998.
- Prefecture (都道府県, todōfuken)
- Japan's top-level administrative division, roughly equivalent to a state or province. There are 47 in total.
- Municipality (市区町村, shikuchōson)
- The city, ward, town, or village level below the prefecture — the second segment shown in this tool's results.
- Town area (町域, chōiki)
- A finer subdivision within a municipality, immediately above the house number. This is the most detailed level a 7-digit postal code can identify.
- Large-recipient postal code (大口事業所個別番号)
- A dedicated postal code assigned to a company or facility that handles a high volume of mail, distinct from the code used by the surrounding town area.
- P.O. box (私書箱, shishobako)
- A collection-only box located inside a post office, which may be assigned its own dedicated postal code.
- Mechanical sorting (機械区分)
- Automated mail-sorting equipment. Japan's postal code system was originally introduced to make this process more efficient.
Frequently Asked Questions
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.