Finally submitting your self-assessment return by the deadline of 31 January 2020. Well we bet you are happy, but often many people realise they have made an error somewhere along the line.

All is not lost! You can change this, read on and find out how.

How do I change my tax return?

If you are in time to file an amended return, what you need to do varies depending on if you filed the original online or on paper.

Online return change process

If you competed the original online, there is a seven-step process:

  1. Sign into your personal tax account with your User ID and password
  2. Select ‘Self-Assessment Account’ if this is not on your screen, you can skip this
  3. Select ‘More Self-Assessment details’
  4. Choose ‘At a glance’ from the left-hand menu
  5. Choose ‘Tax Return options’
  6. Choose the tax year for the year you want to amend
  7. Go into the tax return, make the changes you want to make, and file the return correctly.

Just double check that the return has now submitted and that you have received a submission receipt and that the revised tax calculation is correct.

What about paper returns?

To make a change to a paper return a new one will have to be downloaded. Visit to do this.

Make the changes on the pages you want to and make sure to write ‘Amendment’ on each one, including your name and unique taxpayer reference (UTR) on each page. Finally, send the correct pages to the address that you sent your original to.

But I used commercial software?

You’ll have to contact your software provider to find out how to do this. If the provider does not have this feature, then HMRC will need to be contacted.

What are the deadlines?

You have until 31 January 2021 to make changes to your 2018/29 tax return, otherwise you will have to contact HMRC. In the letter, you will need to say which tax year you are amending and explain why you think you have paid too much or too little and give amounts.

You have four years from the end of the tax year to claim a refund if you have overpaid.

What about changes to my tax bill?

When you amend the return, it may change how much you owe, and any excess should be paid straight away, and any interest will be charged on tax that is paid late.

Your new 2018/19 liability may then impact your 2019/20 account as well.

If you have now ended up paying too much tax, then you should request a repayment from your personal tax account.

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Any questions?

If you’d like a meeting or a Skype call to discuss this, please get in touch with your favourite Liverpool accountant