Two levels of detail
Taiwan introduced its 3+3 postal-code system in 2020. The first three digits identify a postal district; the additional digits provide more detailed sorting information. Knowing the city or district alone is not enough to infer the remaining digits.
What PostalMap currently returns
3+3 · Matched address / 3 · Postal area prefix only. Chunghwa Post · Source retrieved: 2026-10-01. Include the street, house number, city and state or province where applicable. You do not need to know the postal code.
Find the complete delivery code
For the full 3+3 code, use Chunghwa Post’s official lookup with the complete address. Do not append zeros or copy a nearby building’s code. Keep the recipient’s address and the officially matched code together when creating a label.