Which invoice number format does the Dutch tax office allow?
The law (Wet OB art. 35a) requires a sequential number that uniquely identifies the invoice. No mandate on year or layout, only unique and non-skipping per sequence.
Try this first
- 1Pick a simple format like YYYY-NNNN or NNNN-YYYY, both fine with the tax office.
- 2Start at 0001 every January 1, or hold one continuous sequence, pick and stick.
- 3Do not skip numbers, a missing one means you must be able to prove no invoice was sent.
- 4Use separate sequences for credit notes and pro-formas if that helps bookkeeping, provided they are also unique and ascending.
- 5Let the package handle numbering, not manually, otherwise you get duplicates or gaps.
When to bring us in
If you went off-script with manual numbers and want to clean up, we can plan corrections.
See also
- Switching from Exact Online to Yuki, open items and history do not matchPackage migrations stumble on ledger mapping and open AR/AP. Without a mapping table you lose context.
- Twinfield to Exact, dimensions and cost centres go missingTwinfield uses dimensions, Exact uses cost centres and projects. The mapping is not one-to-one.
- Accountant asks for RGS mapping, your ledger does not follow RGSRGS is the Dutch standard chart that SBR filings and accountant software expect. Without mapping, every year-end is manual.
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