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What are the legal requirements for invoice numbers?

Invoice numbers must be unique and unalterable in order to clearly and unambiguously identify an invoice once it is finalized, that is, effective in legal and bookkeeping terms. Applying JustOn's counter and number range functionality, you make sure that these requirements are met.

The fact that some jurisdictions demand sequential invoice numbers does not, however, imply that your invoice numbers must necessarily be consecutive and without gaps in numbering - solely the uniqueness is required. As long as you can provide an explanation for non-consecutive numbers (like a specifically configured counter or just a canceled invoice), breaks in sequence are acceptable. For Germany, for example, the Sales Tax Application Decree states that a gapless sequence of issued invoice numbers is not mandatory ("Umsatzsteuer-Anwendungserlass", section 14.5).


In Draft status, invoice numbers are temporary and of no legal relevance. JustOn creates draft invoice numbers using the following pattern: YYMMDD<first 3 letters of account>. When finalizing invoices, JustOn uses your defined counters to generate the final numbers.