Chinese resident ID number checker

Paste one or more Chinese resident identity numbers, one per line. The tool checks the final check character against the national standard and lists each number's date of birth, age, sex and the region where it was issued; if a number is wrong it says what is wrong. Everything happens in your browser.

How to use it

Paste ID numbers, one per line — a column copied from a spreadsheet works. Spaces and a lower-case x are fine.
The table lists the result, date of birth, age, sex and region for each. When a number fails, the reason is shown: a wrong check character comes with the correct one, and a 17-digit number gets its 18th character calculated.
Click "Copy as table" to copy tab-separated results you can paste straight into Excel.

How the number is built

The 18 characters

Under the national standard GB 11643-1999 a resident identity number is a 17-digit body plus a check character: a 6-digit address code (the county-level division of registered residence), an 8-digit date of birth, a 3-digit sequence number (odd for men, even for women) and finally the check character.

The check character

Each of the 18 characters is multiplied by a positional weight and the products are added; the total must leave a remainder of 1 when divided by 11. The weights for the first 17 positions are 7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2, and the check character's own weight is 1. The resulting check value runs from 0 to 10, with 10 written as the Roman numeral X. A single mistyped digit or two swapped neighbours almost always fails the check. The tool applies this formula and works out the correct last character when a number fails.

Region codes, old and new

The address code is the division code of the place of registered residence when the card was issued; the number does not change after a move or a boundary change. Division codes are set by the Ministry of Civil Affairs and, since 1 September 2025, managed under its Administrative Division Code Measures. The tool uses the county-level codes as of the end of 2025 from the Ministry's national place-name database, supplemented by the Ministry's 2022 and 2023 lists for codes abolished or changed since. For example, Chongqing's Jiangbei (500105) and Yubei (500112) districts are not in the 2025 list but still appear in older numbers, and the tool says so. Codes abolished earlier may not be found; the province or city is shown instead.

Old 15-digit numbers

Early identity numbers had 15 digits — a 6-digit address code, a 6-digit date of birth with a two-digit year, and a 3-digit sequence number — and no check character. The tool reads the year as 19xx, inserts "19", and calculates the check character by the 18-digit rule to give the equivalent 18-digit number.

Examples

Number	Result
11010519491231002X	Valid; born 31 Dec 1949, female, Chaoyang District, Beijing
440304199001011233	Valid; born 1 Jan 1990, male, Futian District, Shenzhen
110105194912310021	Wrong check character; it should be X
11010519491231002	Only 17 digits; the 18th should be X
110105491231002	Old 15-digit number; 18-digit form 11010519491231002X

11010519491231002X is the example number given in GB 11643-1999. Age is counted in completed years: the number of birthdays reached so far.

Limits

Only the format, date of birth and check character are checked. A valid number may still not exist and cannot be tied to a person; identity verification needs an official channel.
The region is where the holder was registered when the card was issued, not where they live now.
Codes abolished long ago may not be found; only the province or city is shown.
Permanent residence cards for foreigners and residence permits for Hong Kong, Macao and Taiwan residents follow different rules and may give inaccurate results.
Only process numbers you are entitled to handle; identity numbers are personal information.

Frequently asked questions

What does the X at the end mean?

It is the check character: when the check value is 10, X keeps the number at 18 characters.

How can I tell sex from the number?

From the 17th digit, the last digit of the sequence number: odd for men, even for women.

Can it look up the holder's name?

No. The number contains no name and the tool connects to no database.

Does a valid check mean the number is real?

Not necessarily. The check catches typing mistakes; an invented number can still pass.

Are numbers uploaded?

No. Everything runs in your browser, even offline.