What do the letter and the second digit in a Taiwan ID number mean?

Question

Weirdo · Accepted Answer

The first letter stands for a municipality, county or city, and the second character is the gender code: 1 is male, 2 is female. The tenth character is a check digit. The new-style resident ID numbers (統一證號) for foreigners use 8 for male and 9 for female.

Under the regulation on the Laws & Regulations Database, a national ID number (統一編號) has ten characters; the first is a letter standing for the municipality, county or city, characters 2 to 10 are digits, the second being the gender code and the tenth the check digit. The National Immigration Agency says a national ID is 1 letter plus 9 digits, with 1 for male and 2 for female in the second position.

A 統一證號 is the identifier used in Taiwan by foreign nationals, nationals without household registration, Hong Kong and Macau residents and mainland China residents. The Agency says numbers issued from January 2, 2021 (ROC year 110) use 1 letter plus 9 digits, with 8 for male and 9 for female in the second position; numbers issued on or before January 1, 2021 are 2 letters plus 8 digits.

Which letter maps to which city or county should be checked against the Ministry of the Interior's household registration announcements; no table is given here, and the check-digit algorithm is not covered.

What do the letter and the second digit in a Taiwan ID number mean?

The national ID format

How resident ID numbers differ

What this page does not cover