Credit invoice and invoice numbers

Best practice for invoices

The numbers consist of <RG-prefix>-<customer-code>-<four-digit year>-<three-digit sequential number>

RG-TUI-2018-012 RG-BAB-2019-001

The three-digit sequential invoice number restarts at the turn of the year with 001. If there really are more than 999 invoices for a customer in one year, the number automatically becomes four digits.

Advantages of this pattern

• The number is suitable as a filename - even on a web server

• The prefix distinguishes between invoice and estimate

• In a file system, files named by invoice number automatically sort by customer, year and sequential number

• The customer code defines a separate number series for the customer


• Customers cannot deduce the agency's revenue

• If customer codes are established in the agency, they are easy to search by

Number ranges for invoice numbers

In addition, the agency software allows maintaining invoice numbers in so-called invoice number series. For example, you can open a separate invoice number series for each customer. This way it is not apparent from the invoice number whether and how many invoices you issue to other customers. German tax law permits maintaining such invoice number series.

Contact us if you have further questions on this topic.