AFM / ΑΦΜ
Validator
Validate the structural format and Module 11 checksum of Greek AFM / ΑΦΜ tax numbers — entirely in your browser, with nothing sent to a server.
About Greek AFM Validation
This tool checks whether the AFM has exactly 9 digits and verifies that the check digit strictly matches the Module 11 algorithm defined by the Greek tax authority AADE.
Supports inputs with or without 'EL'/'GR' prefixes and performs real-time client-side validation with complete privacy.
AFM Validation Algorithm
| Step | Description |
|---|---|
| 1. Clean the input | Remove any formatting and 'EL'/'GR' prefixes, ensuring exactly 9 numeric digits remain. |
| 2. Weight the first 8 digits | Calculate the weighted sum of the first 8 digits multiplied by powers of 2 (256 down to 2). |
| 3. Compute the expected check digit | Compute the expected check digit as (Sum % 11) % 10. |
| 4. Compare with the 9th digit | Compare the expected check digit with the 9th digit. If equal, the AFM is valid. |
Frequently Asked Questions & Technical Guidelines
How does AFM integrate into Greece's myDATA platform?
Every invoice submitted to AADE's myDATA platform carries the supplier's (and often the customer's) AFM so the transaction can be matched to the correct taxpayer's digital books. AADE checks the AFM's checksum and registration status before accepting a myDATA submission.
Does a "Valid" result mean this AFM is officially registered?
No. This tool only checks that the input is structurally and mathematically consistent with the AFM format (9 digits, Module 11 checksum) — it does not confirm the number is actually assigned to a real taxpayer or registered with AADE. It runs entirely in your browser; nothing is sent to a server.