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Common invoicing mistakes

Many invoicing problems come up again and again. Knowing them in advance helps you avoid them.

Forgetting mandatory details

Missing tax ID, address or invoice number. Check the full list in what information must an invoice include before sending it.

Incorrect numbering

Skipping numbers, repeating them, or mixing years without a clear system. See how to number invoices to get it right from the start.

Applying the wrong VAT rate

Using the standard rate when a reduced one applies (or vice versa). If unsure, review how to calculate VAT.

Not keeping a copy of issued invoices

Invoices must be kept for several years by law. Always save a copy as PDF or Excel, not just the email you sent it in.

Confusing an invoice with a quote or proforma

Issuing an invoice too early (when what was actually needed was a quote) can create tax confusion. Review the differences between these documents.

Manual calculation errors

Adding up VAT or the total incorrectly by hand is more common than it seems. Using a tool that calculates automatically, like PreFactur, removes this risk entirely.

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Related articles

  • How to make an invoice step by step
  • How to make a quote step by step
  • How to calculate VAT on an invoice

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