Germany IDNR Validator
Validate German Tax ID
Enter a German Personal Tax Number to verify its validity.
About this Validator
This tool validates German Tax Identification Numbers according to the Federal Central Tax Office requirements.
The validator checks if a given IdNr follows the correct structure and verifies its check digit according to ISO/IEC 7064, MOD 11,10.
This validation only confirms if an IdNr follows the correct format. It does not verify if the number is actually registered with German tax authorities.
What is a German Tax ID (Steuerliche Identifikationsnummer/IdNr)?
IdNr Structure: • Total length: 11 digits • First digit: Never 0 • First 10 digits: - One digit appears twice - One digit never appears - Other digits appear once • Last digit: Check digit
Validation Features: • Length verification • First digit check • Digit frequency check • Pattern validation • Check digit calculation
Used for: • Tax identification • Employment • Banking services • Social security • Official documents • Legal identification
Technical Notes: • ISO/IEC 7064 MOD 11,10 • Random assignment • No personal data embedded • Lifetime validity • Unique identifier
If you need to generate an IdNr for testing purposes, here is a German IdNr Generator