Did you know that the PESEL number consists of 11 digits – includes the date of birth, consecutive number, gender symbol and a control number:

1. date of birth is included in the first six digits in the following order:
   a. the last two digits of the year of birth,
   b. month of birth with the coded age of birth, and
   c. date of birth;
2. the centenary of birth is coded by adding to the number denoting the month of birth:
   a. the number of 80 – in the case of people born in the years 1800-1899,
   b. numbers 0 – in the case of people born in the years 1900-1999,
   c. the number 20 – in the case of people born in the years 2000-2099;
3. single-digit numbers representing the year, month or day are preceded by the digit “0”, subject to the principle set out in point 2;
4. a person’s consecutive number is included in the seventh to tenth digits, with the last digit of the sequence number containing the gender designation: an even digit (including “0”) for women, and an odd digit for men;
5. the eleventh digit is a check number. This digit enables electronic control of the correctness of the assigned identification number.
   Source: Co to jest numer PESEL i jak się go nadaje – Cyfryzacja KPRM – Portal Gov.pl