ID number check / parse

No. The check digit is just an arithmetic self-test of the first 17 characters (ISO 7064 MOD 11-2): anyone can invent 17 digits and complete a correct final digit to get a number that 'passes'. This tool also does not look up specific cities or counties, so it cannot tell whether the number actually exists - it answers exactly two questions: is the format legal (length, characters, date, provincial region code, checksum), and what can be read out of it (birth date, gender, full age, province). To verify a real identity, use face verification with the person's authorization or official channels.

The 15-digit number belongs to the first-generation card, whose birth date had only 6 digits (YYMMDD); the 18-digit number has been standard since the second generation, with an 8-digit birth date (YYYYMMDD). Because first-generation cards were all issued before 2000, the year inside a 15-digit number defaults to 19xx, so upgrading is two steps: insert 19 before the 7th position, then recompute the checksum. For a 15-digit input this page directly outputs the upgraded 18-digit result.

It means the check digit computed from your first 17 characters differs from the final digit you entered - most often one digit was mistyped or two adjacent digits were swapped. The 'expected checksum' shown in the result is the correct final digit recomputed from your 17 characters: if it differs from the actual last digit by exactly one position, a copying slip is almost certain; if it points to an obviously different number, the number itself is most likely invented. Note that X is always treated as uppercase - a typed lowercase x is normalized automatically.

The tool's province table covers the 34 province-level divisions (including Hong Kong, Macao and Taiwan) plus special codes 71 (Taiwan), 81 (Hong Kong), 82 (Macao) and 91 (abroad); if the first two digits are not in the table, it reports unknown. Also, this tool parses only down to province level - it does not match cities or counties - so even when the province matches, that does not prove the first 6 digits correspond to a real district or county.

No. The number is computed only in your own browser: no upload, no storage, closing the page destroys it; the page makes no network request at all, and the number never enters the URL, localStorage / sessionStorage, cookies, or the console. For batch pasting, keep it under 200 numbers per run (a browser rendering limit) - the excess is reported and truncated automatically, and even a thousand-line paste will not freeze the page.