Correcting VAT return errors: what to do after submitting the wrong figures

Submitting a VAT return and then realising the figures were wrong can feel stressful. Maybe you missed an invoice, claimed VAT on something you should not have, entered a sale in the wrong period, or used the wrong VAT rate. Whatever the reason, the important thing is not to ignore it.

VAT mistakes do happen, especially when you are busy running a business, dealing with suppliers, managing cash flow and trying to keep your records up to date. HMRC’s main concern is that you correct the error properly, keep a clear record of what happened and take reasonable care going forward.

If you are unsure how to deal with the correction, working with a VAT return accountant can help you avoid making the same mistake twice.

First, check what type of VAT error you have made

Before you correct anything, you need to understand the mistake. Do not simply change numbers in your accounting software without checking the reason behind the difference.

Common VAT return errors include:

• Sales invoices missed from the VAT return
• Purchase invoices entered twice
• VAT claimed on non-allowable expenses
• Zero-rated and standard-rated sales mixed up
• Credit notes not included
• Reverse charge VAT entered incorrectly
• Bank payments matched to the wrong invoices
• VAT posted in the wrong quarter

Once you know what caused the issue, you can work out whether HMRC allows you to correct it on your next VAT return or whether you need to tell HMRC separately.

This is where accurate records matter. If your bookkeeping is rushed or unclear, it becomes much harder to prove what went wrong and how you corrected it. For many businesses, professional VAT return filing services are not just about submitting the return. They are about making sure the figures behind the return are reliable.

Work out the net value of the error

HMRC looks at the net value of the VAT error. This means you need to compare the VAT you owe HMRC with any VAT HMRC owes you.

For example, if you underpaid VAT by £3,000 but also missed input VAT of £800 that you were entitled to reclaim, the net error is £2,200 owed to HMRC.

If you overpaid VAT, the correction may reduce what you owe on your next return or create an amount due back to you. Either way, you need to keep a note of how you calculated the figure.

You should not guess the amount. Go back to the invoices, receipts, bank records and VAT reports. If you use cloud accounting software, a certified QuickBooks accountant can help review the VAT codes, transaction dates and reports so the correction is based on the right information.

When can you correct the error on your next VAT return?

In many cases, you can correct VAT errors on your next VAT return without writing separately to HMRC.

You can usually do this if the net value of the errors is £10,000 or less. You may also be able to do this if the net error is between £10,000 and £50,000, but it is less than 1% of the total value of your sales shown in box 6 of the VAT return for the period when you found the error.

If the error means you owe more VAT, you add the amount to box 1 on your next return. If the correction means HMRC owes you VAT, you add the amount to box 4.

This sounds simple, but it is still important to keep a proper record. HMRC may later ask why the adjustment was made, which period it related to and how you worked it out. Good VAT accountants services can help you keep this trail clear.

When do you need to tell HMRC separately?

You normally need to notify HMRC separately if the net error is more than £50,000. You also need to tell HMRC if the net error is more than £10,000 and exceeds 1% of box 6 for the period when you discovered it.

Deliberate errors must also be reported separately, regardless of the amount. If you knew the figures were wrong when the return was submitted, or if the error was not accidental, you should get advice before taking any action.

HMRC will usually want details such as:

• How the error happened
• Which VAT period it relates to
• Whether it was an input VAT or output VAT error
• The amount of VAT underpaid or overpaid
• How the correction was calculated
• Whether any customer was charged VAT incorrectly

This is why it is better to deal with the issue early. Leaving it until HMRC contacts you can make the situation harder to manage.

Keep a clear VAT error record

Once you find the mistake, make a separate note in your VAT records. This should include the date you found the error, the VAT period affected, the amount involved and the documents that support the correction.

You should also keep copies of any invoices, credit notes, bank statements, supplier correspondence and accounting reports used to calculate the correction.

Do not rely on memory. If HMRC asks about the correction 12 months later, you need to be able to explain it clearly. This is especially important if your business is growing, you have several income streams, or you trade from more than 1 location.

If you are based locally, accountants in Slough can help you keep your VAT records organised and ready for HMRC, rather than leaving you to piece things together after the event.

Do not change a submitted VAT return directly

Once a VAT return has been submitted, you do not normally go back and edit that return in the same way you might edit an internal report. You correct the issue either through your next VAT return or by notifying HMRC separately, depending on the size and nature of the error.

This is a common area where business owners get confused. The software may show you the corrected figures, but HMRC still needs the correction to be handled in the right way.

Using professional VAT returns services gives you more confidence that the adjustment is being made in the correct box, in the correct period and with the correct supporting records.

Watch out for interest and penalties

If your VAT error means you paid HMRC too little, interest may apply from the original due date. Penalties can also apply if HMRC decides the error was careless or deliberate.

That does not mean every honest mistake leads to a penalty. If you took reasonable care, found the error and corrected it properly, that puts you in a much better position.

Reasonable care can include keeping proper digital records, using the right VAT codes, checking returns before submission and getting professional help where needed. Businesses that use experienced vat accountants are usually better placed to spot issues before they become bigger problems.

Fix the process, not just the number

Correcting the VAT return is only part of the job. You also need to ask why the mistake happened.

Was the bookkeeping done too late? Were invoices missing? Did someone use the wrong VAT code? Were sales and purchases being entered manually without checks? Did you understand the VAT treatment of the transaction?

If you do not fix the process, the same issue can appear again in the next quarter.

For example, a sole trader may start with simple income and expenses, then gradually take on more customers, more suppliers and more VAT complexity. At that stage, sole trader accountancy services can help keep VAT, tax and bookkeeping under control as the business grows.

The same applies if you operate near Berkshire and need local support from accountants in Reading who understand small business VAT, digital records and HMRC deadlines.

When should you get help?

You should consider getting help if the error is large, relates to several VAT periods, involves incorrect VAT rates, affects customers, or you are unsure whether HMRC needs to be notified separately.

You should also get advice if the mistake relates to partial exemption, reverse charge VAT, imports, exports, bad debt relief or VAT on property costs. These areas can be more complex than a simple missed invoice.

A team of vat specialist accountants can review the figures, explain your options and help you correct the error in a way that is accurate and properly recorded.

Final thoughts

Submitting the wrong VAT figures is not ideal, but it can usually be fixed. The key is to act quickly, check the size of the error, keep proper records and use the correct correction method.

Do not ignore the mistake and hope it disappears. VAT errors can affect cash flow, tax planning and HMRC compliance. The sooner you deal with them, the easier they are to manage.

If you have submitted a VAT return with the wrong figures, Asmat & Co Accountants can help you review the error, correct your records and deal with HMRC in the right way. Get in touch today for clear, practical VAT support from a team that understands small businesses, sole traders and growing companies.

FAQs

Can I correct a VAT return after submitting it?

Yes, you can correct VAT return errors after submission. Smaller errors can often be corrected on your next VAT return, while larger or deliberate errors must usually be reported to HMRC separately.

What is the VAT error correction limit?

You can usually correct errors on your next VAT return if the net error is £10,000 or less. Errors between £10,000 and £50,000 may also be corrected this way if they are less than 1% of the total sales figure in box 6 for the period when you found the error.

What happens if I underpaid VAT?

If you underpaid VAT, you may need to add the correction to box 1 of your next VAT return or notify HMRC separately. Interest may apply if the VAT should have been paid earlier.

What happens if I overpaid VAT?

If you overpaid VAT, you may be able to correct this on your next VAT return by adding the amount to box 4. Larger claims or more complex errors may need to be reported to HMRC separately.

Should I get an accountant to correct a VAT error?

It is sensible to get help if you are unsure about the figures, the error is large, several VAT periods are affected, or you do not know whether HMRC needs a separate notification. An accountant can help you correct the error properly and keep the right records.