German Tax ID
Generator
Generate and format valid German Tax ID (Steuer-IdNr) numbers that pass the official ISO/IEC 7064 Mod 11,10 checksum — for software testing and development, entirely in your browser.
About German Tax ID (Steuer-IdNr)
The German Tax ID (Steueridentifikationsnummer or Steuer-ID) is the unique, permanent 11-digit fiscal identifier assigned to every resident in Germany.
It consists of 11 numerical digits, where the first digit is non-zero and the 11th digit is a checksum computed according to ISO 7064 Modulo 11, 10 (DIN 5007-1).
The Steuerliche Identifikationsnummer (IdNr) consists of exactly 11 numeric digits with protected pseudo-random distribution.
Anatomy & Structure of German IdNr
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 to 10 | Base Number | 10 digits | Sequential base where first digit is never 0 and exactly one digit appears twice | 1234567890 |
| 11 | Check Digit | 1 digit | Control digit calculated according to ISO/IEC 7064, Mod 11, 10 standard | 4 |
IdNr Validation Algorithm (ISO/IEC 7064, Mod 11, 10)
| Step | Description |
|---|---|
| 1. Initialize the product | Initialize the accumulated product variable with base value P = 10. |
| 2. Sum each digit | For each of the first 10 digits: compute sum S = (digit + P) % 10. If S is 0, reset S = 10. |
| 3. Update the product | Update product: P = (S × 2) % 11. |
| 4. Compute the check digit candidate | Compute check digit candidate: C = 11 − P. If C is 10, the check digit is 0; otherwise, it equals C. |
| 5. Compare with the 11th digit | Compare with the 11th digit to ensure mathematical validity. |
Frequently Asked Questions & Technical Guidelines
What is the difference between Steuer-IdNr and Steuernummer in Germany?
The Steuer-IdNr is a permanent, lifelong 11-digit number assigned once to every resident and used for all dealings with German tax authorities. The Steuernummer is a separate, non-permanent number assigned by the local tax office (Finanzamt) to a specific tax matter — it changes if you move, switch tax offices, or start a business, and is used mainly on tax returns and invoices.
Are the data in this tool real or official?
No. The numbers generated here are synthetic test data that satisfy the ISO/IEC 7064 Mod 11,10 checksum used by the Steuer-IdNr format, for software development and QA testing only. They are not issued by the BZSt, are not linked to any real person, and must never be used on real tax forms, employment documents, or official filings.