Sweden Personnummer Validator

About this calculator

The Swedish personnummer is the national identity number issued by Skatteverket (the Tax Agency) at birth or on immigration, formatted as YYMMDD-NNNC (or with a plus sign once the holder turns 100): a six-digit birth date, a three-digit serial number, and a final check digit.

That check digit is computed with the Luhn algorithm (mod 10): starting from the rightmost of the first nine digits, alternating digits are doubled, the digits of any two-digit results are summed, all ten values are added together, and the check digit is chosen so the total is a multiple of 10 — the same checksum used to validate credit card numbers.

Because the number embeds a real birth date, it is used far beyond taxation — in banking, BankID authentication, healthcare records, and everyday identification across Sweden — so validating both its format and its Luhn checksum is a common first step before accepting one in a form.