What is a Norwegian fødselsnummer?

A fødselsnummer (birth number) is the 11 digit national identity number Norway gives to everyone in the National Population Register. Banks, doctors, employers and the Tax Administration all use it. It holds the birth date, a three digit individual number and two check digits: DDMMYY III CC.

  • DDMMYY is the birth date with a two digit year.
  • III is the individual number. Its last digit is odd for men and even for women. Its range also tells the century, and the tool reads it the way the stdnum library does: 000 to 499 is 1900 to 1999, 500 to 749 with a year from 55 is 1855 to 1899, 500 to 999 with a year below 40 is 2000 to 2039, and 900 to 999 with a year from 40 is 1940 to 1999.
  • CC are two check digits, each a weighted sum modulo 11 of the digits before it.

Two other numbers share the same layout. A D number goes to people who work or stay in Norway for a short time, and adds 4 to the first digit, so the day reads 41 to 71. An H number is a help number that health services give someone whose real number they don't know, and it adds 4 to the third digit, so the month reads 41 to 52.

Tool description

Type or paste a fødselsnummer, D number or H number. The tool checks the birth date, the individual number range and both check digits as you type, and tells you which part fails.

For a valid number you get the gender, the birth date, the age today, the number type and the check digits. The birth date follows the date format in your regional settings. Spaces are ignored, and the number never leaves your browser.

Features

  • Validates both check digits and the individual number range with the stdnum library
  • Reads the century from the individual number
  • Recognizes D numbers and H numbers and shows the real birth date