If you’ve noticed an error or omission from your tax return, or need to add something at a later time, you can amend your tax return. There are specific timeframes and restrictions for making amendments.
Amendment Deadline #
You can amend your tax return up until 12 months after the submission deadline (31 January). This means you have until the following 31 January to make any changes.
| Tax Year | Submission Deadline | Amendment Deadline |
|---|---|---|
| 2021/22 | 31 January 2023 | 31 January 2024 |
| 2022/23 | 31 January 2024 | 31 January 2025 |
| 2023/24 | 31 January 2025 | 31 January 2026 |
| 2024/25 | 31 January 2026 | 31 January 2027 |
What happens after you amend? #
After submission of any changes, your tax calculation will be updated. This can take a few days, and HMRC will provide an updated statement showing your new tax liability.
- If you’re due a refund: HMRC will process this on your account. You can then request a repayment online using your personal tax account.
- If you’re due to pay more tax: HMRC will calculate the relevant amount. Interest may be charged on any additional tax owed from the original payment deadline (31 January).
- If penalties were applied: Correcting your return won’t automatically remove penalties. However, if the amendment significantly reduces your tax bill, some penalties may be reduced or cancelled.
Common reasons to amend #
You might need to amend your tax return if you:
- Forgot to include a source of income (such as bank interest or dividends)
- Made a mistake calculating your business income or expenses
- Discovered additional allowable expenses after submission
- Entered incorrect figures from your P60 or P45
- Claimed tax reliefs you weren’t entitled to (or forgot to claim ones you were)
- Received updated information from HMRC about your tax code or employment income
How to amend your return #
The method depends on how you submitted your original return.
If you used HMRC’s online system #
- Sign in using your Government Gateway user ID and password
- From ‘Your tax account’, choose ‘Self Assessment account’ (if you do not see this, skip this step)
- Choose ‘More Self Assessment details’
- Choose ‘At a glance’ from the left-hand menu
- Choose ‘Tax return options’
- Choose the tax year for the return you want to amend
- Make your corrections and submit the return again
The system will show your original return with all the previous data, allowing you to make changes where needed.
If you used commercial software #
If you filed through third-party software (such as TaxCalc, QuickBooks, or other accounting software), you’ll need to amend through the same software. Log in to your account, locate the tax return, make your changes, and resubmit.
If MalgraBooks submitted your tax return #
If MalgraBooks prepared and submitted your tax return on your behalf as part of your service package, please contact our accounts team for assistance with amendments.
Please provide details of what needs to be changed and any supporting documentation.
If you submitted your own return through Pulse, contact our team for the return to be removed so that you can resubmit.
If you filed a paper return #
If you submitted a paper tax return, you cannot amend it online. You’ll need to write to HMRC with details of the changes. Include:
- Your name and Unique Taxpayer Reference (UTR)
- The tax year you’re amending
- Clear details of what needs to be changed and why
- The correct figures or information
Send your letter to: Self Assessment, HM Revenue and Customs, BX9 1AS.
Need help? #
If you’re unsure whether you need to amend your return, or need assistance with the amendment process, you can:
- Contact HMRC’s Self Assessment helpline on 0300 200 3310
- Contact MalgraBooks support if our system has submitted your tax return
- Seek advice from a qualified accountant or tax adviser
