What is a Greek AMKA?

The AMKA (Αριθμός Μητρώου Κοινωνικής Ασφάλισης) is the Greek social-security registration number. It has 11 digits: the first six are the date of birth (DDMMYY), the next four are a serial, and the last is a Luhn check digit.

How is the AMKA century decided?

The AMKA stores only a two-digit year, so the century is ambiguous. This tool infers the most likely century from today's date and also shows the alternative year so you can pick the correct one.

How is the AMKA check digit calculated?

The eleventh digit is a Luhn check digit over the first ten. The Luhn algorithm doubles alternate digits, sums the results (subtracting 9 from any double over 9), and the check digit is whatever makes the total a multiple of 10.

How does the gender digit work?

In the serial portion, an even value at the relevant position conventionally indicates female and an odd value male, though this tool focuses on decoding the date of birth and verifying the check digit.

What does DDMMYY mean in the AMKA?

The first six digits encode the date of birth as day, month, two-digit year — for example 150385 is 15 March 1985 (or 2085, hence the century inference).

Does a valid check digit mean the AMKA is real?

No. A correct check digit and a valid date only mean the number is well-formed. It cannot confirm the AMKA was actually issued to a person — only Greek authorities hold that record.

Is my AMKA uploaded anywhere?

No. Everything runs in your browser using client-side JavaScript — the number is never uploaded or stored.

Greece AMKA Decoder — Gera Tools

This tool decodes a Greek AMKA (Αριθμός Μητρώου Κοινωνικής Ασφάλισης — the social-security registration number) into its date of birth and serial, and verifies the trailing Luhn check digit. It’s useful for catching typos in the 11-digit number and reading the birth date it encodes.

How it works

An AMKA is exactly 11 digits, structured as:

Digits 1-6 — date of birth as DDMMYY (day, month, two-digit year).
Digits 7-10 — a serial number.
Digit 11 — a Luhn check digit computed over the first ten digits.

The decoder splits these fields, then re-runs the Luhn algorithm on the first ten digits and compares the result to digit eleven; if they differ, the expected digit is shown so you can spot the error. Because the year is only two digits, the century is ambiguous, so the tool picks the most plausible century (a two-digit year at or below the current one is read as 2000s, otherwise 1900s) and displays the alternative year too.

Example

For the AMKA 15038512340 (illustrative):

Date of birth = 150385 → 15 March 1985 (alternative: 2085)
Serial = 1234
Check digit = 0, compared against the Luhn result over 1503851234

If the Luhn check passes, the number is well-formed; if not, the expected check digit is shown.

Field	Digits	Meaning
Date of birth	1-6	DDMMYY
Serial	7-10	Sequence number
Check digit	11	Luhn over digits 1-10

It runs entirely in your browser, so the number you type is never uploaded. A structurally valid AMKA is not guaranteed to be one that has actually been issued — this tool decodes the encoded fields and verifies the check digit only.