Fødselsnummer – Crossing centuries in Norway

Norwegian Fødselsnummer examples

The Norwegian Fødselsnummer (Birthnumber) is an 11-digit number with 2 control digits. The 10-th digit is a control digit calculated with a weighted modulo 11 variant over the first 9 digits. The 11-th digit is a control digit calculated with another weighted modulo 11 variant over the first 9 digits combined with the 10-th control digit.

As in other countries also this number is based on the date of birth. The first 6 digits represent the birth date as “ddmmyy”. Problem with a 6-digit date is that you cannot identify the century – is a Fødselsnummer starting with 121009 someone born in 1909 or 2009? The Norwegian government has solved this by grouping the following 3 individual digits (individual number) in groups representing a certain era. If you are born between 1854-1899, then your individual number must be between 500 and 749, born between 1900-1999 then your number lies between 000 and 499, and for those born recently between 2000-2039 then your number lies between 500 and 999. With some exceptions for those with an individual number between 900 and 999. Continue reading ‘Fødselsnummer – Crossing centuries in Norway’

Is 270368A172X a correct Finnish Henkilötunnus?

FinlandHetu270368A172X-150x150

The Finnish national personal identification number is the Henkilötunnus, aka Hetu or Ht, has the following format – ddmmyyc999C. For details how to calculate the control character, I refer to the overview blog on National Identification Numbers.

Validating the Hetu 270368A172X shows that it is indeed a correct number. The number 270368172 generates indeed 29 for the modulo 31 proof, represented by control character “X” in the checksum list. The number shows that this is the 86-th girl born on the 27th of March 2068.

The latter might is exactly the start for the discussion on validity. Althought the number itself is well formed, and passes all the automatic checks, dealing with this number in a data quality assessment will raise your digital eyebrow. In the data quality world we will nowadays say that this Hetu is a wrong Hetu, that it cannot be correct.

So always use a bit of human inference when dealing with finnish national personal identification numbers.