🇫🇮Finnish Personal Identity Code (HETU) Validator

HETU validator — Finnish personal identity code online

Our free henkilotunnus (HETU) validator instantly checks the validity of a Finnish personal identity code. The tool verifies the 11-character format, the date of birth taking the century into account, the individual number, and the check character calculated using the mod-31 algorithm. Simply type or paste the number — the validator shows in a fraction of a second whether the HETU is valid and also displays the date of birth and gender.

The Finnish henkilotunnus is widely used in Finland to identify individuals in government, banking, and healthcare systems. If you need to check the validity of a HETU number — for example when verifying customer documents or testing IT systems — this HETU validator will save you manual calculations.

Privacy — fully local

Validation takes place entirely in your browser — not a single digit of the entered number is sent to any external server. You can use the validator even without an internet connection, and your personal data stays exclusively on your device.

Frequently asked questions

What is the Finnish personal identity code HETU (henkilotunnus)?

The henkilotunnus (HETU) is the Finnish personal identity code assigned at birth or upon obtaining resident status in Finland. It has 11 characters in the format DDMMYY+XXXC, where DDMMYY is the date of birth, the century marker indicates the age, XXX is the individual number, and C is the check character.

How does HETU check character validation work?

The validator combines the 6 date-of-birth digits and the 3 individual number digits into a 9-digit integer, calculates the remainder when that number is divided by 31, and reads the character from the 31-character alphabet '0123456789ABCDEFHJKLMNPRSTUVWXY'. The resulting character must match the last character of the HETU.

What does the century marker in a HETU mean?

The century marker (sijoitusmerkki) distinguishes people born in different centuries: '+' means born in the 19th century (1800-1899), '-', 'Y', 'X', 'W', 'V', 'U' indicate the 20th century (1900-1999), and 'A', 'B', 'C', 'D', 'E', 'F' indicate the 21st century (2000-2099).

How do you read gender from a HETU?

Gender is encoded in the three-digit individual number (positions 7-9). Odd values (001, 003, ..., 899) indicate male, while even values (002, 004, ..., 900) indicate female.

Is my data sent to a server?

No. All HETU validation is performed locally in your browser. No data is sent to any server. You can use the validator even without an internet connection.