Generate test henkilötunnus (HETU) numbers
Fictional numbers with correct check digits, for testing software. They may by chance match a real person's number, so never use them to identify or impersonate anyone.
Click a number to copy it.
How a henkilötunnus (HETU) is structured
- DDMMYY: date of birth.
- C: century sign: + for the 1800s, - (or U-Y) for the 1900s, A (or B-F) for the 2000s.
- ZZZ: individual number, 002-899; odd for men, even for women.
- Q: check character.
How the check works
Using the published example 131052-308T:
Join the date and the individual number into one 9-digit number: 131052308. Then 131052308 mod 31 = 25, and position 25 in 0123456789ABCDEFHJKLMNPRSTUVWXY (counting from 0) is T.
A passing check only means the number is well-formed; it doesn't prove the number was issued to anyone.
Finding henkilötunnus (HETU) numbers in text? The EU PII Redaction API finds and replaces national ID numbers from 21 EU/EEA countries, plus names, IBANs, emails and phones, in free text: for example before sending customer messages to an LLM. Free plan available; Python package and MCP server on GitHub.
Frequently asked questions
Why are there new century signs like Y and B?
Since 2023 Finland also uses U-Y (1900s) and B-F (2000s) as century signs, so more numbers can be issued for the same birth date.
What is 900-999 in the individual number?
Those are temporary identifiers, not regular personal identity codes; this validator rejects them.