ID Card Lookup
Validate the 18-digit check digit of a Chinese ID, then parse birth date, gender, age and region
FAQ
Can it look up a name or address?
No, and it should not. This tool does two things: validates the number format against the national standard, and decodes the birth date, sex and registered region (down to district) that the number itself encodes. It connects to no population database and holds no personal data.
How is the checksum calculated?
Per ISO 7064:1983 MOD 11-2 as specified in GB 11643: the first 17 digits are weight-summed, reduced modulo 11 and mapped to the 18th character (0-9 or X).
What is the difference between 15 and 18 digits?
The 15-digit form is the legacy format with a two-digit year and no checksum. The 18-digit form is current, with a four-digit year and a final checksum character. Both are supported.
About this tool
The check digit of an 18-digit Chinese ID follows a fixed algorithm: the first 17 digits are weighted by [7,9,10,5,8,4,2,1,6,3,7,9,10,5,8,4,2], summed, taken modulo 11 and mapped through 10X98765432 to produce the 18th character. This tool applies exactly that rule, so "check digit valid" only means the last character is consistent - it does not prove the number exists. Anyone can generate a number with a correct check digit; real verification requires police or carrier systems.
15-digit numbers predate 1999. They carry no check digit and only a two-digit year (this tool assumes 19xx). For those, only the format and the plausibility of the birth date can be checked, and the result says so explicitly instead of claiming a pass.
Beyond range checks, impossible dates such as 30 February are rejected, and a birth date in the future is flagged. The region table is indexed by the four-digit city code; areas missing from the bundled table fall back to the province name with a note saying the district is not included - that limitation is in the local table, not in the number itself.
Two details people trip over: the Chinese zodiac follows the Gregorian year here, while someone born before Lunar New Year belongs to the previous year animal, so January and early February birthdays need a manual check; and constellations use the usual boundary dates (20 January, 22 December and so on), where some almanacs differ by a day.
Everything is parsed locally - the number never reaches a server. On a shared computer, still clear the field when you are done.