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ID Card Number Lookup

Verify ID card format, check digit, and query province, birth date, etc.

ID Card Structure

An 18-digit ID card consists of:

  • Digits 1-6: Address code (province, city, district)
  • Digits 7-14: Birth date code (YYYYMMDD)
  • Digits 15-17: Sequence code (odd = male, even = female)
  • Digit 18: Check digit (0-9 or X)

This tool only verifies ID card format and check digit validity. It does not store or query personal information.

ID Card Number Lookup Use Cases

  • Verify the authenticity and validity of an ID card number
  • Look up the issuing region of an ID card number
  • Validate birth date information for HR or administrative purposes
  • Check the checksum digit to detect input errors
  • Understand the encoding rules and structure of ID card numbers

Frequently Asked Questions

What do the 18 digits of an ID card number represent?

The first 6 digits are the address code representing the administrative division. Digits 7-14 represent the birth date in YYYYMMDD format. Digits 15-17 are sequence codes, where the 17th digit indicates gender (odd for male, even for female). The 18th digit is a checksum for validation.

Why does my ID number show as invalid?

Possible reasons include: incorrect number of digits, checksum mismatch, unreasonable birth date (e.g., future date), or invalid address code. Please double-check the number you entered.

Does this tool store my ID card information?

No. All verification and parsing operations are performed locally in your browser. The ID card number is never sent to any server, stored, or logged. You can use this tool with confidence.

ID Card Number Encoding Rules

The Chinese second-generation resident ID card number consists of 18 digits following the GB 11643-1999 standard. The first 6 digits are the address code based on national administrative division codes, precise to county level. Digits 7-14 record the birth date in YYYYMMDD format.

The 18th digit uses the ISO 7064:1983, MOD 11-2 checksum system. The calculation multiplies each of the first 17 digits by corresponding weight factors, sums them, and takes modulo 11. The remainder maps to a checksum character. If the remainder is 2, the checksum is X.