Steuerliche Identifikationsnummer
Germany · Individuals
Paste or type the number — punctuation is optional.
Other identifiers
Europe
Asia and the Middle East
Oceania
What this check does — and what it cannot do
This tool checks the number's structure and its check digit, using the published algorithm for that document. A number that passes is well formed: it is arithmetically consistent and could have been issued.
It cannot tell you whether the number was actually issued, whether it is active, or who it belongs to. Only the issuing tax authority can confirm that, through its own lookup service. Treat a passing result as "worth submitting", never as proof of identity.
Calculated in your browser. Nothing you enter is sent anywhere.
Only 0.359% of eleven-digit numbers can be a Steuer-ID — about one in 279
Two independent rules apply. The eleventh digit is an ISO/IEC 7064 MOD 11,10 checksum, and the first ten must contain exactly one repeated digit — one value appearing twice, or since 2016 three times but never three in a row. Testing 300,000 random eleven-digit numbers, only 0.359% satisfied both.
How it works
- Runs the ISO/IEC 7064 MOD 11,10 procedure over the first ten digits.
- Enforces the repetition rule, including the post-2016 three-times case.
- Rejects a leading zero, which a Steuer-ID never has.
product = 10 for each of the first ten digits: sum = (digit + product) mod 10, and 10 if that is 0 product = (2 × sum) mod 11 check digit = 11 − product, written as 0 when that gives 10 first ten digits: exactly one value repeats (twice, or three times since 2016, but never three consecutively) · first digit is never 0
Worked example
The published example 86095742719.
- the first ten digits are 8 6 0 9 5 7 4 2 7 1
- the digit 7 appears twice and the digit 3 not at all — the rule holds
- the leading digit is 8, so the zero rule holds
- the MOD 11,10 procedure over those ten digits produces 9
- the eleventh digit is 9, so the number is well formed
A number constrained twice over. The structural rule is unusual: most identifiers check arithmetic alone, whereas this one also dictates how the digits may repeat.
Reading the result
- The repetition rule is not decoration. It rules out lazy sequences and makes many mistyped numbers fail on structure before the checksum is even reached, which is why so few random numbers get through.
- The Steuer-ID is permanent and follows a person for life, unlike the Steuernummer issued by a local tax office, which changes when you move. If a form asks for one, the two are not interchangeable.
- No generator is offered. This identifies a person, and a well-formed Steuer-ID is exactly what a fraudulent form needs — unlike a company tax number there is no legitimate reason to synthesise one.
Common questions
- Why is my number rejected when the checksum looks right?
- Probably the repetition rule. Among the first ten digits exactly one value may repeat; if two different digits each appear twice, or a digit appears three times consecutively, the number is not a valid Steuer-ID no matter what the check digit says.
- Is this the same as my Steuernummer?
- No. The Steuer-ID is the eleven-digit lifetime number issued by the Bundeszentralamt für Steuern. The Steuernummer comes from your local tax office, has a different format, and changes if you move.