CNP Validator (Romania Personal Identity Number)
Validate authenticity, calendar date consistency, and Modulo 11 checksum of Romanian CNP numbers.
About Romanian CNP Validation
This tool inspects all 13 digits of the CNP, verifying the sex/century digit, calendar validity of the encoded birth date (leap years and month bounds), county code, and official Modulo 11 checksum.
Secure, client-side real-time validation executed in browser memory without sending data to remote endpoints.
CNP Validation Algorithm
- Confirm the input contains exactly 13 decimal numeric digits.
- Decode century from digit S and validate birth date plausibility.
- Calculate weighted sum using key [2, 7, 9, 1, 4, 6, 3, 5, 8, 2, 7, 9].
- Apply Modulo 11 (if remainder is 10, expected check digit is 1; otherwise, equals remainder).
- Compare with the 13th digit of the CNP.