TL;DR: Free Taiwan national ID validator: verifies the area letter (including the special mapping table), gender digit, and mod-10 check digit locally, parsing gender. Format validation only.
This tool runs entirely in your browser. Open DevTools → Network panel and search your input — it appears in no request.
Usage Guide
A Taiwan national ID is 10 characters: an area letter + a gender digit (1 male / 2 female for nationals; 8/9 for resident certificates) + a 7-digit serial + a mod-10 check digit. This tool validates with the public algorithm: the letter maps to a two-digit code (mind the special values I=34, O=35, W=32, X=30, Y=31), tens digit weighs 1 and units 9, then eight digits weigh 8 down to 1; the total must be divisible by 10. Gender is parsed on success.
1. The letter table is not alphabetical
The area codes are not a simple A=10 sequence — five letters were historically pushed to the end (I=34, O=35, W=32, X=30, Y=31) and J is only 18. A hand-rolled validator that walks A-Z in order will be wrong; this is the scheme’s most famous trap. Gender digits 3-7 have never been allocated and can be rejected outright.