Amend a tax return
A return can be corrected after it has been sent: income you forgot, a figure you typed wrongly, a relief you did not claim, a section that should not be there. Online it takes a few minutes and HMRC recalculates the year straight away. Pick what you need to change below and we tell you exactly where it goes, then walk through the amend screens with your figure already in the box.
HMRC's systems need three days to process the original. Until then the Amend option is greyed out.
You can amend online until 12 months after the 31 January filing deadline for that year. Sign in, Self Assessment, the year, Tax return options, Amend tax return.
Once the window has closed, write to HMRC with the year, your UTR and what changed. If you paid too much, that is a claim for overpayment relief, allowed up to four years after the end of the tax year. If you owe more, HMRC raises an assessment.
A paper return is amended by sending the corrected pages with 'amendment' written on each, your name and UTR. A return filed through software is amended through the software; contact HMRC if the software cannot.
Choose the change and type the figure. We say which question to switch on, which page and box it goes in, and what it does to your bill. Then the amend screens, with the figure already in.
You can amend the 2026/27 return online until 31 January 2029
Sign in, choose the year, Tax return options, Amend tax return. If you filed in the last 72 hours, wait until the option appears.
The full-year figure from the P60, statement or letter. It goes into the walkthrough box below.
For pay or a pension, from the same P60 or P45. It is credited against the bill.
From the original calculation, so you can compare.
How to make this change
Several pensions? Add them together in box 11 and their tax in box 12. The State Pension goes in box 8, not here.
Every screen from signing in to the confirmation, as a list or as they look online, with your figure in the box.
Sign in, open the return you sent, change the figure, and the service works out the new bill. Six screens. You must wait 72 hours after filing before the amend option appears, and the online window closes 12 months after the filing deadline.
Type the figure above and it fills the box on screen 4.
Every box can be typed into, here or on the redrawn screens, and what you type stays in the box while you read the rest.
Your Self Assessment account lists every year with a return. Choose the one you need to change.
Government Gateway user ID
The same sign-in you used to file. If you filed through software, amend through the software instead.
Tax year to amend
Pick the year from the list on your Self Assessment home page. Each year has its own return and its own window.
The year's options include Amend tax return. It is greyed out for 72 hours after you file, and disappears 12 months after the filing deadline.
Choose Amend tax return
Under Tax return options for that year. If it is missing, either 72 hours have not passed since you filed, or the 12-month window has closed and you need to write to HMRC instead.
72 hours have passed since you filed
HMRC's systems need three days to process the original before a change can be made to it.
If the change adds a kind of income or a claim the return did not have, switch its question to Yes here; the pages then appear. If it changes a figure already there, skip straight to the page.
Switch on the section you need
Only if the change adds something the return did not have: a pension, a job, rental income, a relief. Answer Yes to its question on Tailor your return and the pages appear at the end of the return.
The pages open exactly as you sent them. Overtype the box that was wrong or empty; leave everything else as it is.
The figure being added or corrected
Type the right figure over the wrong one, or into the empty box. The page and box number are in the guide above.
Tax taken off it, if any
For pay or a pension, the tax deducted goes in the box next to the income. It is credited against the bill, so missing it out overstates what you owe.
The service recalculates the whole year. Compare the new total with the old one before you submit: the difference is what you will pay or be repaid.
Total due on the return you sent
From your original calculation, so you can see the difference the change makes.
Total due after the change
The service shows the new calculation before you submit. More than before: the difference is due now, with interest from the original due date. Less: HMRC repays the difference.
The same declaration as the original return. Keep the reference; the statement updates within three days.
Declaration
The information is correct and complete to the best of your knowledge, the same wording as the original return.
Submission reference
Shown on the confirmation screen and emailed to you. Keep it with the original.
Your statement updates within three days with the extra tax or the refund, plus interest either way from the original due date. Payments on account are recalculated too. Pay any extra straight away to stop interest running; a refund goes to the bank details on the return.
Correct a Self Assessment tax return (GOV.UK)