Steuer-IdNr
Steueridentifikationsnummer. German personal tax identification number.
Use this page for field meaning, local checksum math, examples, and integration notes. Official identity, registry, account, or tax status still belongs to the owning system.
Entity Summary
- Jurisdiction
- Germany (DE)
- Category
- German Personal Tax Identification Number
- Format
- 11 numeric digits
- Local signal
- Eleven-digit IdNr, repetition guard, checksum
What is Steuer-IdNr?
Steuer-IdNr (steuerliche Identifikationsnummer)
The Steuer-IdNr (German: steuerliche Identifikationsnummer, Personal Tax Identification Number) is the mandatory tax code assigned to every resident in Germany.
Introduced in 2008 to replace the old tax numbers, it remains assigned to an individual for life (and is even kept for 20 years after death).
Issuing Authority
It is issued and administered by the Federal Central Tax Office of Germany (Bundeszentralamt für Steuern - BZSt).
Visual Structure Breakdown
Standard German Steuer-ID numbers consist of exactly 11 digits structured as:
[ S S S S S S S S S S ] [ C ]| Field | Positions | Description |
|---|---|---|
| SSSSSSSSSS | 1–10 | Unique personal serial tax number. The first digit must not be 0. One digit must repeat exactly two or three times (others must be unique). |
| C | 11 | Control checksum digit. |
Modulo Checksum Details
The German Steuer-ID control digit uses the international standard ISO 7064 (MOD 11-10) checksum method.
Algorithm Formula
Let \(d_1, \dots, d_{11}\) be the digits of the Steuer-ID.
Initialize a remainder term \(R = 10\).
For each digit \(i = 1\) to \(10\):
1. Add the digit to the remainder:
\[S = (R + d_i) \pmod{10}\]
If \(S = 0\), set \(S = 10\).
2. Compute the new remainder:
\[R = (S \times 2) \pmod{11}\]
The final checksum control digit \(C\) is computed as:
\[C = (11 - R) \pmod{10}\]
This control value must match the 11th digit \(d_{11}\).
Validation Examples
| Sample Input | Description | Status |
|---|---|---|
| 82938175409 | Valid Steuer-ID — Standard valid German personal tax identification number. | ✓ Valid |
| 11111111111 | Invalid Repetition — Fails the German rule requiring exactly one digit to repeat exactly two or three times. | ✗ Invalid |
| 12345 | Too Short — Must be exactly 11 numeric digits. | ✗ Invalid |
Implementation Guidance
Developer Guidelines
When implementing Steuer-ID validation:
- Input must be exactly 11 numeric digits.
- The first digit must not be
0. - Regex:
/^[1-9]\d{10}$/. - Validate the digit repetition rule: Out of the first 10 digits, exactly one digit must repeat either 2 or 3 times. The remaining digits must appear only once.
- Apply the ISO 7064 MOD 11-10 check algorithm.
function validateSteuerID(id) {
if (!/^[1-9]\d{10}$/.test(id)) return false;
const counts = {};
for (let i = 0; i < 10; i++) {
counts[id[i]] = (counts[id[i]] || 0) + 1;
}
const vals = Object.values(counts);
let doubleCount = vals.filter(v => v === 2).length;
let tripleCount = vals.filter(v => v === 3).length;
if (!((doubleCount === 1 && tripleCount === 0) || (doubleCount === 0 && tripleCount === 1))) {
return false;
}
let r = 10;
for (let i = 0; i < 10; i++) {
let s = (r + parseInt(id[i])) % 10;
if (s === 0) s = 10;
r = (s * 2) % 11;
}
const checksum = (11 - r) % 10;
return checksum === parseInt(id[10]);
}Frequently Asked Questions
When do I receive a Steueridentifikationsnummer?
Every child born in Germany receives their Steuer-ID shortly after birth registration. Foreign residents receive theirs upon registering their residence at the local citizen registration office (Bürgeramt).
Can a Steuer-ID be deleted?
No. To prevent duplicate registrations and tax evasion, the number remains active during the person's life and is stored for statistics for decades after.
Official Registry Sources
References
1. Federal Central Tax Office (Germany): Public portal explaining ID assignments. Official BZSt portal.
2. German Fiscal Code (Abgabenordnung - AO) § 139b: Statutory definition of the tax identification number registry format.