The 13-digit tax number for ELSTER
Updated: July 2026 · ~4 min read · eBilanz Fabrik (a tool, not tax advice)
In short: your usual German tax number (Steuernummer) looks different depending on the federal state — for example 217/5322/3153. For electronic transmission to the Finanzamt it is converted into a unified 13-digit format. That conversion follows fixed per-state rules; you do not have to work it out yourself.
Why 13 digits at all?
The Steuernummer is issued by the tax offices of the federal states and historically has its own format in each state (different lengths and separators). For nationwide-uniform electronic processing via ELSTER and the ERiC interface, it is turned into a unified 13-digit number. This lets every transmission be assigned unambiguously to the correct tax office and tax account.
A schematic example to illustrate the principle — the concrete conversion depends on the individual federal state and is not an official calculation for your specific case. Without guarantee.
What is the 13-digit number made of?
The idea behind the unified format: the state-specific tax number is prefixed with the four-digit federal tax-office number; the remaining digits map the district and distinguishing numbers plus a check digit. The result is always 13 digits. The exact assignment of digits is set in a fixed implementation scheme per federal state.
The Steuernummer is not the tax identification number
A common mix-up — the two numbers are easily confused:
| Feature | Steuernummer (tax number) | Tax identification number (IdNr) |
|---|---|---|
| Legal basis | Issued by the Finanzamt | Section 139b AO |
| Digits | per federal state (13 digits electronically) | 11 digits |
| Applies to | a tax account / company | a natural person |
| Changeable? | yes (e.g. on a move / change of office) | no, lifelong and constant |
| For the e-Bilanz? | yes — the Steuernummer | no |
For the e-Bilanz of your GmbH or UG, the Steuernummer is what counts — in 13-digit format when transmitted electronically.
Where do I find my tax number?
Your Steuernummer appears on every tax notice and usually on correspondence from your Finanzamt. Do not confuse it with the VAT identification number (USt-IdNr, starting with „DE“), which is used for intra-EU trade.
With eBilanz Fabrik you type your tax number exactly as it appears on your notice. The software handles the conversion into the 13-digit transmission format. To the Finanzamt via ERiC in under 10 minutes, from 24,95 €.
Create your e-Bilanz →FAQ
What is the 13-digit tax number?
The unified format of your Steuernummer for electronic transmission to the Finanzamt via ELSTER/ERiC. It is formed by a fixed conversion from your state-specific tax number. Without guarantee.
Is the Steuernummer the same as the tax identification number?
No. The Steuernummer is assigned by the Finanzamt for a tax account and can change. The tax identification number under Section 139b AO is a lifelong, unchanging 11-digit number for natural persons. For the e-Bilanz the Steuernummer is what counts. Without guarantee.
Do I have to calculate the 13-digit tax number myself?
No. With eBilanz Fabrik you enter your usual tax number exactly as it appears on your notice. The software handles the conversion into the 13-digit transmission format. Without guarantee.
eBilanz Fabrik is a transmission tool and gives no tax advice. Registered ELSTER software vendor. Information on number formats and the process without guarantee; the tax administration's specifications and the statutory rules govern (incl. Section 139b AO). Price: 24,95 € (regularly 29,95 €) per filing, net plus 19 % VAT.