Why do some Chinese ID numbers end in X?

The last character is a check digit. Multiply the first 17 digits by the weights 7 9 10 5 8 4 2 1 6 3 7 9 10 5 8 4 2, add them up and take the remainder modulo 11; remainders 0–10 map to 1 0 X 9 8 7 6 5 4 3 2. A check value of 10 is written as the Roman numeral X, so X is valid and can be typed in either case.

Does passing the check mean the ID is genuine?

No. It only shows the number follows the encoding rules — check digit, date and region code. It cannot tell whether the number was actually issued or who it belongs to. Identity verification has to go through the police or a licensed real-name verification service.

Is the region where the person lives now?

No. The first six digits are the administrative code of the place where the ID was first issued, and they never change when someone moves or when divisions are reorganised, so the region may be an old or renamed one. This tool covers provinces and prefecture-level cities, not counties.

How is a 15-digit ID upgraded to 18 digits?

15-digit numbers were issued before 1999 and have a two-digit birth year. Insert “19” after the sixth digit to get 17 digits, then append the check digit computed with the algorithm above. Enter a 15-digit number in single mode to see the 18-digit version and copy it.

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🔰Chinese ID Number Validator - Check Digit, Region, Birthday

Validate 18-digit Chinese resident ID numbers: check digit, date of birth and region code, plus the decoded birthday, gender, age, zodiac and issuing region. Also upgrades 15-digit numbers, computes a missing check digit and validates lists in bulk, all locally in your browser.

Free · No sign-up · Runs in your browserLast updated: 2026-10-26

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How to use Chinese ID Number Validator

1Choose Validate one, Batch validate or Check digit
2Type or paste the ID number (one per line in batch mode)
3Read the result, region, birth date and gender — upgrade a 15-digit number or export the batch as CSV

FAQ

Why do some Chinese ID numbers end in X?: The last character is a check digit. Multiply the first 17 digits by the weights 7 9 10 5 8 4 2 1 6 3 7 9 10 5 8 4 2, add them up and take the remainder modulo 11; remainders 0–10 map to 1 0 X 9 8 7 6 5 4 3 2. A check value of 10 is written as the Roman numeral X, so X is valid and can be typed in either case.
Does passing the check mean the ID is genuine?: No. It only shows the number follows the encoding rules — check digit, date and region code. It cannot tell whether the number was actually issued or who it belongs to. Identity verification has to go through the police or a licensed real-name verification service.
Is the region where the person lives now?: No. The first six digits are the administrative code of the place where the ID was first issued, and they never change when someone moves or when divisions are reorganised, so the region may be an old or renamed one. This tool covers provinces and prefecture-level cities, not counties.
How is a 15-digit ID upgraded to 18 digits?: 15-digit numbers were issued before 1999 and have a two-digit birth year. Insert “19” after the sixth digit to get 17 digits, then append the check digit computed with the algorithm above. Enter a 15-digit number in single mode to see the 18-digit version and copy it.