Amending a tax return
If, after you have filed your tax return, you become aware that an entry is incorrect, you can amend that return.
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When to amend a tax return
If you realise you have made a mistake on your tax return, you should amend it as soon as possible to correct the error.
We explain below what the deadline is for amending a return and what to do if you miss the deadline.
You can amend your return any number of times before the amendment deadline.
You have up to 12 months from 31 January following the end of the tax year to which the tax return relates to make the amendments. If the notice to file the return was issued after 31 October, you can amend the tax return within 15 months of that notice being issued.
Therefore, if you need to amend your 2021/22 tax return you normally have until 31 January 2024 to make the amendment. This applies whether you manually filed a paper version of the return or you filed online. Or if, for example, you did not receive a notice requiring you to file your tax return for 2021/22 until 12 December 2022, then you can amend it up until 11 March 2024.
If you have missed the deadline
If you need to amend your tax return outside of the above time limits, you usually still need to notify HMRC so that your tax position can be corrected.
If additional tax is due, you should usually write to HMRC or otherwise, depending on the circumstances, make a disclosure. We recommend you seek advice in this situation as you may owe penalties as well as late payment interest on the unpaid amounts.
If tax is overpaid due to the mistake, you may be able to make a claim for overpayment relief to obtain a refund. You can read about how to do this on our page Self assessment tax refunds.
How to make an amendment
If you filed your original tax return online, you can make the amendment online through HMRC’s self assessment portal. You can also make the amendment on paper by writing to HMRC.
If you used third party software to file the return originally, you should use this to make the amendment.
Paper filers should make any amendments on paper. For more information, see GOV.UK.
Self-Employment Income Support Scheme claimants
If you have claimed the fourth and/or fifth self-employment income support scheme (SEISS) grants, you will need to consider whether amendments to your tax return(s) mean you were not actually eligible to claim these grants or whether the grant(s) received should have been less.