Made a mistake on an invoice that has already been sent? Do not change it. An invoice number should be unique and consecutive, and a sent invoice is a document of record. You correct it with a credit note.
What is a credit note?
A credit note is the mirror image of an invoice: the same lines with negative amounts. Together with the original invoice the balance is zero. A credit note has a number of its own and refers to the invoice it corrects.
Steps
- Open the final invoice and make a credit note from it.
- Check the lines and the VAT rate. Want to credit only part of it? Change the amounts.
- Finalise the credit note and send it to your customer.
- If needed, make a new, correct invoice afterwards.
What happens to the VAT?
The VAT on the credit note reduces the VAT you have to pay in the period in which you make it. That brings your VAT return right again.
In Moonlight Bookkeeping a final invoice gets a consecutive number and can no longer be changed. You correct through a credit note; the bookings follow the documents by themselves.
This guide is general information, not tax advice. Check the current rules for your situation with the tax authority or your bookkeeper.