How to Void or Correct an Invoice You Already Sent

To void an invoice, you keep the original document and its number, mark it void in your records with the reason and the date, tell the client in writing that it is cancelled, and issue a replacement under the next number in your sequence that says which invoice it replaces. You never delete a sent invoice and you never reuse its number. Which fix you use depends on two questions: has the client seen it, and has the client paid it? Unsent means edit freely. Sent and unpaid means void and reissue. Paid means a credit note. A typo in a field that does not touch money means a corrected copy and a one-line email.

That rule set works the same whether you invoice from accounting software, a spreadsheet, or a PDF you generated in a browser tab. The buttons differ between apps. The logic does not, and the logic is what keeps your records clean when an accountant, a client's finance team or a tax office looks at them later.

What is the difference between voiding, deleting and correcting?

These three words get used as if they mean the same thing. They do not, and mixing them up is how people end up with gaps in their numbering they cannot explain.

Deleting removes the invoice from your records as if it never existed. It is only safe for a draft that nobody else has seen and that you never logged anywhere. Once an invoice has gone to a client, it exists in their inbox and possibly in their accounts payable system, so deleting your copy does not make it disappear. It just means you are the only party without a record of it.

Voiding cancels an invoice while keeping it. The document stays on file with its number, marked void, with its value treated as zero. The void record is what answers the question "what happened to invoice 2026-0014?" before anyone asks it.

Correcting covers everything else: editing a draft, sending a corrected copy of a document whose amounts were right, or issuing a credit note against an invoice that was already paid or already counted in a tax return.

A short way to hold it in your head: delete is for things that never left your machine, void is for things that left but never turned into money, and a credit note is for things that did.

Which fix does your invoice need?

Here is the whole decision in one table. Find the row that matches your situation and do what the last column says.

Has it been sent?	Has it been paid?	What is wrong	What to do
No	No	Anything	Edit the draft and send it. No record needed.
Yes	No	Amount, rate, hours, tax, currency, line items	Void the original, reissue under the next number, reference the old number
Yes	No	Client wants it cancelled entirely	Void it and confirm the cancellation in writing
Yes	No	Typo in a non-money field (address, PO number, spelling, contact)	Corrected copy with the same number and amounts, plus a one-line email
Yes	Yes	Client overpaid, or you overcharged	Credit note against the original, then refund or apply it to the next invoice
Yes	Yes	You undercharged	Leave the original alone and send a new invoice for the difference
Yes	Yes	Typo in a non-money field	Corrected copy marked paid, only if the client asks for one
Either	Either	You invoiced the wrong client	Void it, tell the wrong recipient to disregard it, invoice the right client fresh

Two things decide the row. Money changing is the big one: if any figure a finance team would type into their system is different, the client needs a new document, not an edited one. Payment is the other: once money has moved against an invoice, that invoice is part of a completed transaction and you correct it with a new document rather than changing the old one.

When can you simply edit and resend?

When the client has not seen it. An invoice sitting in your drafts, or one you generated and then noticed a mistake in before you hit send, is still a working document. Fix it and move on.

The one grey area is an invoice you already logged. If you keep a ledger or spreadsheet and you already wrote 2026-0014 into it before spotting the error, the cleanest habit is still to treat that number as spent: mark it void in the ledger and send the corrected version as 2026-0015. It costs one line. The invoice numbering system post covers why a gap with a void note next to it is fine, and why a number used twice is not.

The other case where editing is acceptable is a typo that touches no money: your own address is wrong, the client's company name is misspelled, you left off the purchase order number their finance team asked for. The amounts on the document are right, so nothing needs to be cancelled. Send a corrected copy with the same number, the same date and the same totals, and say in one line what changed. What you should not do is quietly change a price on a document that keeps the same number. The client's copy and yours now disagree, and there is nothing on either one that says which is right.

How do you void and reissue without breaking your numbering?

This is the case you will hit most often: the invoice went out, it has not been paid, and something with a dollar sign on it is wrong. You billed 32 hours instead of 23, applied last year's rate, or charged tax you should not have. Here is the sequence.

Keep the original. Do not delete the file or the saved record. Add a note to it: "VOID 2026-09-24. Wrong hours. Replaced by 2026-0015."
Mark it void in your ledger. Whatever you use to track what you have issued, the row for 2026-0014 gets a void status and a zero balance, not a deletion.
Create the replacement under the next number. 2026-0015, dated today, with the corrected figures. Use a fresh due date calculated from the new issue date, not the old one; you cannot fairly hold a client to payment terms on a document they only just received.
Reference the original on the replacement. One line in the notes: "Replaces invoice 2026-0014, which is cancelled." That sentence is what lets the client's accounts payable team close the first record instead of paying both.
Send both facts in one email. The cancellation and the replacement travel together, so nobody pays the wrong one in the gap between two messages. The template is further down.

In billable.dev this takes about a minute. Open the saved invoice, click Duplicate, and the copy picks up the next number in your sequence automatically. Fix the line that was wrong, add the "Replaces 2026-0014" note, and save it. Then open the original and add the void note so your history still explains itself.

Why not reuse 2026-0014 for the corrected version? Because the client may already have it. Many accounts payable systems check new invoices against the supplier's previous invoice numbers, and a second document with a number they have already recorded is likely to be held as a possible duplicate, which stalls the payment you were trying to speed up. A new number with an explicit reference avoids the question entirely.

The rules behind this vary by country, but the direction is consistent. In the EU, the European Commission's VAT invoicing rules list a unique sequential number identifying the invoice as a required field on a full VAT invoice, which is hard to square with deleting or renumbering documents after the fact. In the US, the IRS recordkeeping guidance lets you choose any system that clearly shows your income and expenses, and says you must keep records as long as needed to prove the income on a return. A void record with a reason is exactly the kind of entry that makes the income side reconcile.

What if the client already paid the wrong amount?

Then the original invoice is closed and it stays closed. You fix the difference with a new document, and which document depends on which way the error ran.

The client paid too much. Issue a credit note. A credit note is its own document with its own number, dated today, that names the original invoice, states the amount being credited and why, and says whether the credit will be refunded or applied to a future invoice. On a retainer, applying it to next month is usually simplest for both sides; on a finished project, refund it. In the UK, HMRC is specific about what a credit note needs if VAT is involved: its VAT guidance on valid credit notes requires an identifying number and date of issue, a description of what is being credited, the rate and amount of VAT credited, and the number and date of the original invoice, and says the credit note must be issued within 14 days of the refund payment being made.

The client paid too little because you undercharged. Do not reissue the whole thing. Send a new invoice, under the next number, for the difference only, with a note like "Balance on invoice 2026-0014: 9 hours omitted from the original." Asking a client who has already paid to go back into their system and replace a completed record is more work for them than paying a small second invoice.

The client paid the right amount but the invoice has a cosmetic error. Usually leave it. If they ask for a corrected copy for their records, send one with the same number, marked paid, with a note saying what changed.

What do you tell the client when you send the corrected invoice?

Less than you think. The goal is that someone who was not part of the project, reading the email three weeks from now, knows which document to pay and which to ignore. Put both invoice numbers in the subject line and keep the body to four sentences.

For a void and reissue:

Subject: Corrected invoice 2026-0015 (replaces 2026-0014)

Hi Dana,

I made an error on invoice 2026-0014: it billed 32 hours
instead of 23. Please disregard it; it is cancelled.

The corrected invoice, 2026-0015, is attached for $2,070,
due October 8. Nothing else has changed.

Sorry for the extra step.
Sam

For a corrected copy where the amount did not change:

Subject: Updated copy of invoice 2026-0014 (PO number added)

Hi Dana,

Attached is an updated copy of invoice 2026-0014 with your
PO number added. The amount and due date are unchanged.
If you already filed the first copy, this one replaces it.

Sam

Three things make these work. The subject line carries both numbers, so the email is findable by either one. The body says what was wrong in one plain clause, without a paragraph of apology. And it says explicitly what the client should do with the old document. For the rest of the mechanics of sending (attaching versus linking, timing, who to address), the invoice email post has the full templates.

A checklist before you hit send on the fix

The original is still on file, marked void or referenced, not deleted
The replacement has a new number, and the old number appears in its notes
The due date is calculated from the new issue date
The totals on the replacement match what the client should actually pay
The email subject names both invoice numbers
Your ledger shows the void, so the gap in your sequence has an answer next to it

If you are fixing an invoice because a line item was vague and the client pushed back, it is worth tightening the template while you are at it. The post on what belongs on a software development invoice covers the fields that tend to trigger questions.

FAQ

Can I delete an invoice I already sent?

You can delete your own copy, but you should not, and it does not achieve anything useful. The client still has the invoice, possibly already entered in their accounts payable system, so deleting it only removes your record of something that still exists elsewhere. It also leaves an unexplained gap in your numbering. Void it instead: keep the file, mark it void with a reason and date, and issue a replacement if one is needed.

Does a voided invoice keep its number?

Yes. The number is spent the moment the invoice is issued, and a voided invoice keeps it permanently. The replacement always gets the next number in your sequence, never the voided one. That way every number maps to exactly one document forever, and a gap in the sequence always has a void record explaining it.

Do I need a credit note to fix an invoice?

Only when money has already moved, or when the original has already been counted in a tax return. If the invoice is unpaid, voiding it and reissuing under a new number is enough. If the client paid and you owe them money back, or you are VAT registered and need to reduce the VAT you charged, a credit note is the document that does that.

How do I fix the wrong tax on an invoice?

Treat it like any other money error. If the invoice is unpaid, void it and reissue with the correct tax, referencing the original number. If it has been paid and you overcharged tax, issue a credit note for the excess and refund or apply it. If you undercharged, send a new invoice for the difference. If you are registered for VAT or sales tax, check your tax authority's rules or ask an accountant, since some regimes set specific requirements for how tax corrections are documented and when they must be issued.

Found the mistake already? Open billable.dev, load the saved invoice, click Duplicate, fix the line, and reissue it under the next number. Nothing to sign up for, and your invoices stay in your browser.

This post is general information, not tax or legal advice. Rules on invoice corrections, credit notes and record retention differ by country and by tax registration. Check your own position with a qualified professional in your jurisdiction.