German VAT ID
Validator
Check whether a German VAT ID (USt-IdNr) is correctly formatted and passes the official ISO/IEC 7064 Mod 11,10 checksum — entirely in your browser.
About German VAT ID (USt-IdNr) Validation
The German VAT Identification Number (USt-IdNr.) is the business tax identification number for companies conducting B2B transactions across the EU.
It is composed of the prefix "DE" followed by 9 digits, where the final digit is verified using the ISO 7064 Modulo 11, 10 algorithm.
Anatomy & Structure of German VAT ID (USt-IdNr.)
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 & 2 | Country (ISO) | 2 letters | Sovereign country code of Germany (ISO 3166-1 alpha-2) | DE |
| 3 to 10 | Company Serial | 8 digits | Unique corporate identifier assigned by BZSt | 12345678 |
| 11 | Check Digit | 1 digit | Control digit calculated per ISO/IEC 7064, Mod 11, 10 standard | 9 |
German VAT ID Validation Algorithm (ISO/IEC 7064, Mod 11, 10)
| Step | Description |
|---|---|
| 1. Initialize the product | Initialize the product variable with base value P = 10. |
| 2. Sum each digit | For each of the 8 numeric digits: compute S = (digit + P) % 10. If S = 0, reset S = 10. |
| 3. Update the product | Update product accumulator: P = (S × 2) % 11. |
| 4. Compute the check digit candidate | Calculate check digit candidate: C = 11 − P. If C = 10, the check digit is 0; otherwise C. |
| 5. Compare with the 9th digit | Confirm match against the 9th numeric digit (11th character of the DE string). |
Frequently Asked Questions & Technical Guidelines
How do I validate a German USt-IdNr using the ISO 7064 algorithm?
Strip the "DE" prefix, take the 8 numeric digits that follow, and run them through the ISO/IEC 7064 Mod 11,10 recurrence described above. If the resulting check digit matches the 9th numeric digit, the number is structurally valid. This only confirms the checksum — confirming the VAT ID is actually registered to a business requires the EU's official VIES lookup service.
Are the data in this tool real or official?
No. This validator only checks whether a number satisfies the ISO/IEC 7064 Mod 11,10 checksum used by the USt-IdNr format — it does not look up or confirm any real company registration. A result of "valid" means the number is mathematically well-formed, not that it belongs to a real business.