How invoice numbers work

Most countries ask for invoice numbers that follow one another without gaps, so that a missing invoice would show. Fillfold makes this automatic.

When a number is given

A draft has no number. The number is given at the moment you choose Issue invoice: Fillfold takes the next number of the series, dates the invoice today and locks it. If issuing fails, for example because a required detail is missing, no number is used. Deleting a draft therefore never leaves a gap.

Credit notes have their own series, so invoices and credit notes never share a number.

Choose the format

Open Invoices, then Invoice settings, section Numbering.

1. In Invoice numbers, write the format. {YYYY} is replaced by the year of the invoice, and {SEQ:4} by the number on at least 4 digits (change 4 for another width). Capital letters, digits and - / _ are kept as typed: INV-{YYYY}-{SEQ:4} gives INV-2026-0001.
2. In Credit note numbers, write a different format, for example CN-{YYYY}-{SEQ:4}.
3. Tick Start again at 1 every year if you want each year to begin at 0001. The format must then contain {YYYY}.
4. In Start at number, enter where to continue if you come from other software, for example 57.
5. Choose Save settings. The hint under each field shows the next number.

Fillfold suggests a format for your country: F2026-0001 and AV2026-0001 in France, RE-2026-0001 in Germany, INV-2026-0001 in Ireland and the United Kingdom.

Locked after the first invoice

Once your first invoice is issued, the country and the numbering can no longer change. A note in Invoice settings says so. This keeps one continuous sequence for your accountant and the tax authority.

Good to know

• Numbers are given in the order invoices are issued, and the issue date is always the day of issue, so the dates follow the numbers.
• The number is printed on the PDF, used as the payment reference next to your IBAN, and listed in the CSV export.

See Create and send an invoice and Credit notes.