Åk 6–9

2.3 Personal Identity Number
A personal identity number is a unique designation for every person who resides in Sweden. It was introduced in 1947.  Personal numbers are given out by the tax department when you register for residency.

The personal identity number consists of what year, month, and day you were born. Besides these numbers, are an additional four digits which are called birth numbers.  In everyday conversation they are called the “last four” numbers.


91 = Birth Year 1991
09 = Birth Month September
22 = Day of Birth in September

69xx: county code before the year 1990. After 1990, it has been randomly generated.
693x: Even numbers = girls, odd numbers = boys
xxx7: Checksum which is calculated by using the other numbers.

From this personal identity number, we can see that the person was born on the 22nd of September, 1991 and is a guy.