What HMRC checks before your UK VAT return online

What HMRC checks when you submit

Your software sends the return to HMRC through the Making Tax Digital VAT service. Within seconds, HMRC either accepts it and gives a receipt, or rejects it with an error code. It checks that:

• Your software is authorised for the VAT number, through a current connection made with your Government Gateway sign-in
• The VAT number is valid and registered
• The period is one of your open periods on HMRC's records
• The period has ended, so you are not filing early
• No return has already been accepted for that period
• The declaration is confirmed, meaning you have said the figures are true and complete
• Every box is present and in the right format, within HMRC's limits
• The sums add up: Box 3 equals Box 1 plus Box 2, and Box 5 is the difference between Box 3 and Box 4

What HMRC checks later

Acceptance only means the return passed those automatic checks. It does not mean HMRC agrees with your figures. HMRC can look at these later, usually in a compliance check:

• Whether your figures are right, for example the VAT rates you charged and the VAT you reclaimed
• Whether you kept digital records of your sales and purchases
• Whether the figures moved digitally from your records to your return, with no retyping by hand
• Whether you have evidence, such as VAT invoices, for what you reclaimed

HMRC chooses which businesses to check using its own risk assessment, so unusual changes from one return to the next can attract attention.

Checked at submission or later

The rules for each box

• Boxes 1 to 4: pounds and pence, with no more than 2 decimal places. They can be negative, for example after a credit note.
• Box 3: must equal Box 1 plus Box 2.
• Box 5: the difference between Box 3 and Box 4, always shown as a positive number, even when HMRC owes you a repayment.
• Boxes 6 to 9: whole pounds only, with no pence.
• Boxes 2, 8 and 9: only for goods moved between Northern Ireland and the EU. Everyone else enters 0.
• No blanks: enter 0 in any box that does not apply.

For what goes in each box, see HMRC's guide VAT Notice 700/12.

The most common rejections and how to fix them

• Already filed: a return for the period has been accepted, perhaps by your accountant or other software. Do not send it again. Correct any error on your next return.
• Period not ended: wait until the day after the period end date.
• Period not recognised: refresh your periods from HMRC and choose the open one, rather than typing the dates in.
• Not authorised or connection expired: reconnect your software with the Government Gateway login that holds the VAT registration.
• Box errors: remove pence from Boxes 6 to 9, check Box 3 and Box 5 add up, and enter 0 rather than leaving a box blank.

Use the error lookup above to see what your exact error means. If you are close to the deadline, fix the problem and resubmit on time, as a rejected return does not count as filed.

After HMRC accepts your return

• Keep the receipt: HMRC gives a receipt reference for every accepted return.
• Pay on time: pay any VAT due by the deadline, usually 1 month and 7 days after the end of the period.
• Fix mistakes the right way: you cannot resubmit an accepted return. If the error was not deliberate and is no more than £10,000, or up to 1% of your Box 6 figure with a maximum of £50,000, correct it on your next return. Larger or deliberate errors must be reported to HMRC separately, for example on form VAT652.
• Keep your records for at least 6 years.

Final thoughts

HMRC's checks at submission are about the structure of your return, not your figures. File for the right open period, keep your software connected, follow the box rules, and most rejections disappear. Accuracy is still your responsibility, so keep good digital records for the checks HMRC can make later.

Disclaimer: This guide gives general information, not advice for your business. If you are unsure how the rules apply to you, speak to an accountant or contact HMRC.