Taiwan National ID & Resident Certificate Validator (身分證/居留證)

The Taiwan National Identification Number consists of 10 alphanumeric characters: one capital letter followed by 9 digits. The initial letter indicates the administrative county or city of original household registration (e.g., A for Taipei, B for Taichung, F for New Taipei). Each letter maps to a two-digit integer according to official government standards, with the tens digit multiplied by 1 and the ones digit multiplied by 9.

The second character denotes gender: 1 for male and 2 for female citizens. The third through ninth digits are sequential numbers weighted by decreasing multipliers [8, 7, 6, 5, 4, 3, 2]. The tenth character is the checksum digit with a weight of 1. The grand total of all weighted products must be divisible by 10 (modulo 10 = 0) for the ID to be valid.

For foreign residents, the National Immigration Agency introduced the New Alien Resident Certificate (ARC) format on January 2, 2021. The new format adopts the syntax: 1 letter + digit (8 for male, 9 for female) + 8 digits, identical to the citizen format. The legacy ARC format used two letters followed by 8 digits.

Privacy notice: This tool runs 100% locally in your browser. No personal identification numbers are transmitted across the internet or stored in any database. Passing validation indicates correct mathematical checksum syntax and does not confirm active civil registry existence.