Free Chinese ID Number Checker (身份证号码校验)

Worked example

Paste 11010519491231002X, the example number the page uses for its sample. The tool shows "Valid format and check digit", the type "Mainland resident ID (18 digits)", the province 北京市, the birth date 1949-12-31 (with an age worked out from your device's date) and the sex Female. The check character comes from the first 17 digits: each digit is multiplied by a fixed weight, the products add up to 167, and 167 mod 11 is 2, which maps to X. Change the last character to 1 and the result becomes "Check digit does not match" with the line "At least one character is wrong, or two are swapped. Compare it with the card again." Paste the old 15-digit number 110105491231002 and the type reads "Mainland resident ID (old 15 digits)" with an "18-digit number" 11010519491231002X and a Copy button. "Try a sample" loads four lines (those two, the Taiwan number A123456789 and the Hong Kong number A123456(3)) and reports "4 of 4 valid".

Which settings to use, and the limits

• Know what a pass means. A pass means the number is well formed: the right length and characters, a birth date that exists (not before 1900 and not after today's date on your device), a known province code and a correct check character. It does not mean the number was issued or belongs to anyone, and only the issuing authority can confirm that. The page reads only the province from the first two digits, not the city or county, because county codes change and an old ID keeps the code it was issued with.
• Use it for the other card types too. Besides the 18-character Mainland ID it reads the old 15-digit card, the residence permit for Hong Kong, Macao and Taiwan residents (numbers starting 81, 82 or 83, shown for example as "Residence permit for Hong Kong residents"), the foreign permanent resident ID card (starts with 9, province read from digits 2 and 3), a Taiwan ID number (one letter, then 9 digits whose first digit is 1, 2, 8 or 9) and a Hong Kong ID card (one or two letters, six digits and a check digit that is 0 to 9 or A). The result line shows the type, and for Taiwan the place of first registration.
• Type it any way it was written. Spaces, dashes, dots and underscores are removed, full-width digits and letters are converted, and a lower-case x becomes X. Hong Kong numbers can be typed with or without the brackets, as A123456(3) or A1234563, and the result shows the bracketed form. Other punctuation, such as a colon in "ID:", is not removed and gives "Not a recognised ID number format".
• Check a whole column at once. Paste one number per line. Blank lines are skipped and at most 2,000 lines are checked. With two or more lines you get a summary such as "3 of 4 valid" and a table that shows the first 500 rows. "Download CSV" saves every checked row with the columns ID number, Type, Result, Birth date, Sex, Province or region and 18-digit number. Each number is written with a leading tab so Excel keeps all 18 characters instead of showing 1.10105E+17.
• Hide the digits before you take a screenshot. Tick "Hide the middle digits on screen and in the CSV" to show only the first 4 and last 4 characters, so an 18-character number reads as 1101, ten asterisks, then 002X. The table, the single result, the upgraded 18-digit number and the CSV all use the masked form. The Copy button next to an upgraded 18-digit number still copies the full number.
• Nothing is looked up or saved. The check is plain arithmetic done in your browser, and the page says "Checked in this browser. Numbers are never sent, stored or put in the page address." For that reason there is no share link and no lookup against any database. The sample is the standard's example number rather than a real person's. The age next to a birth date uses the date on your device.

Common problems and how to fix them

It says "Not a recognised ID number format".

The text is not one of the shapes the tool knows. A Mainland number has 18 characters (17 digits and a digit or X) or, on old cards, 15 digits. A Taiwan number is a letter and 9 digits; a Hong Kong number is 1 or 2 letters, 6 digits and a check digit or A. Count the characters first, since a dropped or doubled digit is the usual cause. A pasted label such as "ID:", two numbers on one line, or a Taiwan-style number with two letters and 8 digits also lands here, and so does a Taiwan number whose second character is not 1, 2, 8 or 9.

It says "Check digit does not match".

The number has the right shape, but the final check character does not fit the other digits. The tool's own advice is that at least one character is wrong, or two are swapped, so compare it with the card again. For a Mainland number the page still shows the province, birth date and sex it read, which can help you spot the typo. It does not suggest a corrected number.

It says "Impossible birth date".

Positions 7 to 14 of an 18-digit number must be a real calendar date, not before 1900 and not later than today's date on your device. A 15-digit number holds the date in positions 7 to 12 as YYMMDD, and the tool reads the year as 19YY. Month 13, day 31 in a 30-day month and 29 February in a non-leap year all fail, so a digit in that block is probably wrong. If your device clock is wrong, a recent birth date can be flagged as being in the future.

It says "Unknown province code".

The first two digits are not a province code the tool knows: 11 to 15, 21 to 23, 31 to 37, 41 to 46, 50 to 54, 61 to 65, or 71, 81, 82 and 83. This check runs before the birth date and the check digit, so it is the first problem you see if the start of the number is mistyped. For a foreign permanent resident card, which starts with 9, the code is read from digits 2 and 3 instead.

A spreadsheet shows 1.10105E+17, or drops the final X, after you paste the numbers in.

A spreadsheet can read an 18-digit number as a quantity and change it. Use "Download CSV", where each number starts with a tab so it opens as text, or format the column as Text before you paste. The CSV is UTF-8 with a byte order mark so the Chinese province names display correctly.

How it compares

This does what a form validator does with a pattern and a short formula: it checks length, characters, province, birth date and the check digit, and it also reads out the province, birth date and sex and handles the old 15-digit card, Taiwan numbers and Hong Kong numbers. It cannot tell you whether a card was issued, is genuine, is still in force or belongs to the person in front of you, because that needs the issuing authority. It does not look up counties, so it will not name the city of issue. Use it to catch typing mistakes in a list before you submit it, not as proof of identity.