Invoice number generator

What German law requires of an invoice number

Under § 14 (4) no. 4 of the German VAT Act (UStG), an invoice must contain, among other things, “a sequential number with one or more number ranges, assigned once by the invoice issuer to identify the invoice”. In other words, a number that identifies each invoice unambiguously and is used only once. The law allows one or several number ranges for this.

The text does not say how the number is built. The patterns in this generator are therefore examples of common notations, not requirements. Which variant suits your business is best clarified with your tax adviser. If you are not subject to German law, check the rules of your own country.

A note on the word “credit note”

In the German VAT Act, a “Gutschrift” has a meaning of its own: it is an invoice issued by the recipient of a supply instead of the supplier (§ 14 (2) UStG). It is not the same as the everyday credit note, which corrects an earlier invoice. How you number correction or cancellation documents is not answered by this generator.

What the generator cannot do

• It does not know which numbers you have already issued and does not check your records for gaps or duplicates.
• It does not replace bookkeeping: issuing real numbers belongs in your invoicing software or number register.

For demos and tests, the sample shop database contains orders with order numbers and totals, and the test IBAN generator creates account numbers for sample invoices.