Correct VAT return errors

Types of VAT return errors

Errors on VAT returns generally fall into these categories:

• Over-claimed input tax - you reclaimed more VAT on purchases than you were entitled to
• Under-declared output tax - you didn't charge or report enough VAT on sales
• Under-claimed input tax - you didn't reclaim VAT you were entitled to
• Over-declared output tax - you reported too much VAT on sales
• Wrong box entries - figures entered in the wrong box (for example, including VAT in boxes 6-9 which should exclude VAT)
• Timing errors - transactions included in the wrong VAT period

The first two error types mean you owe HMRC money. The second two mean HMRC owes you. All errors should be corrected, but errors in HMRC's favour are obviously less urgent.

Common mistakes that lead to errors

Understanding what causes VAT return errors helps you avoid them in future:

Error correction thresholds

The method you use to correct an error depends on the net value of all errors you've discovered on previous returns. The net value is the total of all errors added together (some may cancel each other out).

Working out if you're within the threshold

To determine which correction method to use:

1. Calculate the net value of all errors you've discovered (add together increases and decreases in VAT owed)
2. If the net error is £10,000 or less - you can adjust your next return
3. If the net error is between £10,000 and £50,000 - check if it's less than 1% of your Box 6 figure for the current period
4. If the net error exceeds £50,000, or is more than 1% of Box 6 turnover - you must notify HMRC separately

Example: You discover you under-claimed £8,000 input tax and over-declared £3,000 output tax. The net error is £11,000 (in your favour). Your current period Box 6 is £1,500,000. 1% of £1,500,000 = £15,000. Since £11,000 is less than £15,000 AND less than £50,000, you can adjust on your next return.

Correcting small errors on your next return

If your error is within the threshold, you can correct it by adjusting the relevant boxes on your next VAT return. This is the simplest method.

Correcting larger errors (voluntary disclosure)

If your error exceeds the threshold for adjusting on your next return, you must report it separately to HMRC. This is called a voluntary disclosure or error notification.

You can also choose to make a voluntary disclosure even for smaller errors - for example, if you want a formal record that you've corrected the error.

How to make a voluntary disclosure

From 8 September 2025, you can no longer use form VAT652. Instead, you must report errors using the online error correction service or in writing.

Time limits for correcting errors

You can correct errors from VAT returns submitted in the previous 4 years, measured from the end of the VAT period in which the error occurred.

Penalties for VAT errors

Penalties for VAT errors depend on whether the error was careless, deliberate, or simply a genuine mistake - and whether you disclosed it voluntarily or HMRC discovered it.

Why voluntary disclosure matters

The penalty ranges show that voluntary (unprompted) disclosure always results in a lower maximum penalty than if HMRC discovers the error themselves. An unprompted disclosure is one you make before HMRC gives any indication they intend to check your returns.

Once HMRC writes to you about a check or sends an enquiry letter, any disclosure becomes 'prompted' and the penalty range increases.

Appealing a penalty

If HMRC issues a penalty, you may be able to appeal if you have a reasonable excuse:

What happens if you don't correct errors

Failing to correct known errors on your VAT returns is risky. HMRC may:

• Discover the error during a VAT inspection or desk-based review
• Cross-reference your returns against other data (supplier returns, bank records, customs declarations)
• Assess additional VAT plus interest from when it was originally due
• Charge higher penalties (prompted disclosure rates)
• In serious cases, pursue criminal prosecution for fraud

Interest on underpaid VAT accrues from the date the VAT was originally due, regardless of when the error is corrected. The longer you wait, the more interest accumulates.

Interest on late VAT

When you correct an error that means you owe HMRC additional VAT, interest is charged from when the VAT was originally due.

If HMRC owes you money

When you correct an error that means HMRC owes you VAT (for example, you under-claimed input tax), you're entitled to a refund. However, you won't receive interest on historical underclaims - the refund only covers the VAT amount itself.

Once HMRC agrees the refund, they should pay within 30 days. If they take longer without good reason, you may be entitled to repayment interest.

Record keeping for error corrections

Whenever you correct a VAT error, keep detailed records showing:

• The VAT period(s) the error affected
• The nature of the error and how it happened
• How you calculated the correction
• The date you made the correction
• The method used (adjustment on return or voluntary disclosure)
• Any correspondence with HMRC

Keep these records for at least 6 years. HMRC may ask to see evidence of how you corrected errors during a VAT inspection.

Getting help with VAT errors

If you're unsure how to correct an error, or the error is complex, consider getting professional help. An accountant or VAT specialist can:

• Calculate the correct adjustment
• Advise on the best correction method
• Help prepare a voluntary disclosure
• Negotiate with HMRC on penalties
• Represent you if HMRC raises an enquiry

The cost of professional advice is often worthwhile for larger errors or complex situations, particularly if penalties may apply.

Related VAT penalties

Errors on VAT returns may also interact with the penalty regime for late submission and late payment. Understanding these helps you manage your overall compliance.

Late submission penalties

Late payment penalties