What a credit note is
A credit note is a document you send to a client to reduce or cancel an amount you have already invoiced. Think of it as a negative invoice. If you invoiced €2,400 and later agree that €400 of it should not have been charged, you do not edit the original invoice. You issue a credit note for €400, linked to that invoice, and the client now owes €2,000. In some countries and accounting tools it is called a credit memo, but it works the same way. A credit note is a formal accounting record, with its own number and date, and it sits alongside your invoices in your books. It is the normal, correct way to fix a mistake or reflect a change after an invoice has been sent, and clients and accountants expect to see it.
When you need one
Credit notes cover any situation where a client should end up paying less than the invoice says. Common examples include a pricing or quantity error, such as billing 12 hours instead of 10; returned goods, where a customer sends back part or all of an order; a discount or goodwill gesture agreed after the invoice went out, perhaps because a deadline slipped; a cancelled project or order that was invoiced in advance; a duplicate invoice sent by mistake; and an overpayment you want to record as a credit on the client's account. In each case the original invoice was a real document that may already be in the client's system or your VAT records. The credit note corrects it while keeping a clear trail of what happened and why.
Why you cannot just edit or delete the invoice
It is tempting to open the original invoice, change the amount and send it again, or delete it and start over. Once an invoice has been sent, that causes problems. The client may already have entered it into their accounts payable system, so a changed version under the same number creates confusion. If you are VAT registered, the original may already be included in a filed VAT return, and changing it afterwards breaks the link between your records and your return. Deleting invoices also leaves gaps in your number sequence, which many tax authorities treat as a warning sign; see our guide to invoice numbering. A credit note avoids all of this. The original stays exactly as sent, and the correction is a separate, dated record.
What to include on a credit note
A credit note should contain much of the same information as an invoice, so the client and any tax inspector can match it up. Include your business details and, if registered, your VAT number; the client's details; a clear title saying it is a credit note; a unique credit note number; the date of issue; the number and date of the original invoice it relates to; a description of what is being credited and why, such as 'Correction: 2 hours billed in error'; the amount being credited, broken down into net amount, VAT rate and VAT amount where VAT applies; and the total credit. Some countries have specific requirements for credit notes, especially for VAT, so check yours. Keeping the reason short and factual helps everyone later.
Full and partial credit notes, with an example
A full credit note cancels an invoice entirely. Say you invoiced a client €2,400 for a workshop that was then cancelled. You issue a credit note for €2,400 that references the original invoice, and the balance owed drops to zero. If the workshop is rescheduled, you send a new invoice with a new number. A partial credit note reduces an invoice. Suppose the €2,400 invoice covered three days of work, but one half-day was dropped at the client's request. You agree to reduce the fee by €400 and issue a credit note for that amount. The client now owes €2,000. If VAT applies, the credit note reduces the VAT too: at an illustrative 20 percent rate, the credit would be €400 plus €80 VAT, a total of €480.
Refund, or credit on account?
A credit note records that the client owes less. What happens next depends on whether they have already paid. If the invoice is still unpaid, the credit note simply reduces the balance, and the client pays the remaining amount. If they have already paid in full, you have two options. You can refund the credited amount to them, which is recorded as a payment out against the credit note. Or, if you will keep working together, you can leave the credit on their account and apply it to their next invoice. Agree with the client which they prefer, and confirm it in writing. Either way, the credit note comes first: it is the document that justifies the refund or the reduced balance, and it keeps your receivables accurate.
How credit notes affect your books and VAT
In your books, a credit note reduces your sales, in the same way an invoice increases them. On accrual basis, it lowers your revenue in the period the credit note is dated. On cash basis, what matters is the money actually received or refunded. Your accounts receivable also drops by the credited amount, so an invoice that has been fully credited no longer appears as money owed to you. If you are VAT registered, the VAT on the credit note reduces your output VAT, usually in the period in which the credit note is issued, though rules differ by country. This is one reason credit notes are so important: they put the correction into the right VAT return, with a clear document behind it if anyone asks.
Avoiding the need for credit notes
Credit notes are a normal part of business, but issuing lots of them often points to problems earlier in the process. A few habits cut them down. Double-check quantities, rates and client details before sending, especially on invoices you build from a previous one. Agree scope and price in writing before the work starts, so there is less to dispute afterwards. For projects with uncertain scope, invoice a deposit and then the balance at the end, rather than the full amount upfront. Review invoices once more before they go out to large clients with strict accounts payable teams. And when something does change, issue the credit note promptly rather than waiting, so the client's records and yours stay aligned. Our guide on creating a professional invoice covers the basics.
Credit notes without the paperwork
Kelvo Books has credit notes built in. Create a full or partial credit note against any invoice you have sent, and it is recorded alongside the original. The client's balance updates, your accounts receivable aging reflects the change, VAT tracking picks up the correction, and your live profit and loss shows the reduced revenue. Your original invoices stay untouched, so your numbering and VAT records remain clean. The free plan includes 10 invoices a month, unlimited clients and expenses, and the P&L. Pro at €7 a month adds unlimited invoices, reminders and recurring billing. Start at books.kelvo.app.