What format is a German VAT number?

A German VAT number (Umsatzsteuer-Identifikationsnummer, USt-IdNr) is the prefix DE followed by exactly 9 digits, for example DE136695976. The first digit is non-zero.

How is the check digit computed?

It uses the ISO 7064 MOD 11,10 iterative scheme over the first 8 digits. Starting from a product of 10, each digit updates a running value, and the 9th digit is the resulting check digit. The number is valid only if it matches.

Does a valid check digit mean the company is VAT-registered?

No. A valid check digit only confirms the number is well-formed. To confirm a business is actively VAT-registered for cross-border trade, check the EU VIES service. This tool performs no online lookup.

Why do I need to validate a VAT number?

For EU B2B sales, a valid VAT number lets you apply the reverse-charge mechanism and zero-rate the supply. Invoicing with an invalid number can make you liable for the VAT, so format and check-digit validation is a sensible first step.

Can I include spaces or the DE prefix?

Yes. The tool strips spaces and accepts the number with or without the DE prefix, then validates the 9-digit body. It will tell you if the length or prefix is wrong.

Germany VAT Number Validator

A German VAT number (Umsatzsteuer-Identifikationsnummer, USt-IdNr) identifies a business for EU cross-border trade. It is the country prefix DE followed by 9 digits, where the final digit is a check digit. This validator confirms the format and runs the official check-digit algorithm in your browser — handy before applying the reverse charge on a B2B invoice.

How it works

The German check digit uses the ISO 7064 MOD 11,10 iterative scheme over the first 8 digits:

Strip spaces and the DE prefix so you have 9 digits.
Set a running product P = 10.
For each of the first 8 digits d: compute M = (P + d) mod 10; if M = 0 then M = 10; then set P = (2 × M) mod 11.
The expected check digit is (11 - P) mod 10.
The VAT number is valid if the expected check digit equals the 9th digit.

Example

Validate DE136695976 → body 136695976, first 8 digits 13669597, check digit 6.

Iterating the MOD-11,10 scheme over 13669597 yields an expected check digit of 6, which matches the 9th digit, so the number is valid.

Notes

A valid check digit confirms the number is well-formed, not that the business is currently VAT-registered. To confirm active registration for intra-EU supplies, query the EU VIES system. Everything here runs locally — your VAT number never leaves your device.