How is a personnummer structured?

It is the date of birth (YYMMDD or YYYYMMDD), a separator (- normally, + if the person is 100 or older), a three-digit birth number, and a final Luhn check digit. The second-to-last digit of the birth number encodes sex — odd for male, even for female.

How is the check digit verified?

The last digit is a Luhn (modulo-10) check digit computed over the ten significant digits YYMMDDNNN. This tool recomputes it with the standard Luhn algorithm and compares it to the digit you entered.

Is my personnummer sent anywhere?

No. Decoding is entirely client-side. The number never leaves your browser and there are no network requests. The tool does not query the Skatteverket register.

Sweden Personnummer Decoder & Luhn Validator

Sweden personnummer decoder

Enter a Swedish personnummer and the tool decodes the date of birth, the birth number and the gender, then verifies the final Luhn check digit.

It accepts the 10-digit form (YYMMDD-NNNC, with + marking people aged 100 or more) and the 12-digit form (YYYYMMDDNNNC). The second-to-last digit of the birth number encodes sex — odd means male, even means female — and the final digit is validated with the Luhn algorithm.

Privacy-first: your personnummer is processed entirely in your browser — nothing is uploaded or sent anywhere. The tool does not query the Skatteverket population register.