International · Validation
Estonian isikukood validator.
Check an Estonian personal identification code (isikukood), the 11-digit number used on ID cards and e-Residency. The tool recomputes the check digit and reads the birth date and sex from the code. Format and checksum only.
How it works: multiply the first 10 digits by 1, 2, 3, 4, 5, 6, 7, 8, 9, 1 and take the total mod 11. If the result is 10, repeat with weights 3, 4, 5, 6, 7, 8, 9, 1, 2, 3; if that is also 10 the check digit is 0. The result must equal the 11th digit.
Inputs
Result
Enter a number and press Validate.
How the isikukood check works
| Step | What happens |
|---|---|
| 1 | Digit 1 gives century and sex: 1 and 2 are the 1800s, 3 and 4 the 1900s, 5 and 6 the 2000s, 7 and 8 the 2100s; odd is male, even is female |
| 2 | Digits 2 to 7 are the birth date YYMMDD; the date must exist |
| 3 | First pass: weights 1, 2, 3, 4, 5, 6, 7, 8, 9, 1 on digits 1 to 10, mod 11 |
| 4 | If the remainder is 10, second pass with weights 3, 4, 5, 6, 7, 8, 9, 1, 2, 3; a second 10 becomes 0 |
| 5 | The result must equal digit 11 |
Worked example
36805280109: 3×1 + 6×2 + 8×3 + 0×4 + 5×5 + 2×6 + 8×7 + 0×8 + 1×9 + 0×1 = 141. 141 mod 11 = 9, which is the last digit. The code reads as a man born on 28 May 1968.
Why there can be two passes
Mod 11 can give 10, which does not fit in one digit. The Estonian scheme then uses a second set of weights, and only if that also gives 10 is the check digit 0.
Checksum only, not a register lookup
A passing result means the characters are consistent with each other. It does not confirm that the number was issued or that it belongs to anyone. Use it as a typo and format check. For the same kind of check on a Canadian number, see the SIN validator, or browse all ID and number validators.
Sources: python-stdnum, stdnum/ee/ik.py; Wikipedia, National identification number (Estonia).
Frequently asked questions
What is an Estonian isikukood?
It is the personal identification code assigned to Estonian residents. It appears on ID cards, in the population register and in e-Residency.
What do the first digits of an isikukood mean?
The first digit encodes century and sex. Digits 2 to 7 are the birth date as YYMMDD. Digits 8 to 10 are a serial number and the last digit is the check digit.
Does a passing check mean the person exists?
No. It shows the 11 digits are consistent. The population register is the only place that can confirm a code was issued.
Format and checksum only
This tool checks format and checksum entirely in your browser. It does not query any register, and a passing result is not proof the number was issued or belongs to anyone. Nothing you type is transmitted, stored, or logged.