We all make mistakes from time to time. But, if you’ve made a mistake on your Self-Assessment Tax Return, can you change it?

The good news is that, if you have just spotted a mistake, then don’t panic. There are ways to amend it. Find out more in our video.

Is it possible to amend my tax return?

The deadline for filing Self-Assessment Tax Returns is 31 January each year.  If you have already filed your return but have noticed that you have made a mistake, then do not panic as you can amend it.

What are the time limits?

If you have submitted your tax return, but you want to make a change then it is possible to amend it if you do it within twelve months of the filing deadline.

For example, if you have submitted your 2018/19 return online by the deadline of 31 January 2020, then you will have until 31 January 2021 to amend it.

What are the restrictions?

If it is later than 12 months after the due date, then you will no longer be able to file an amended tax-return.

If this is the case, then you would have to write to HMRC to tell them error and ask them to change it.

How do I correct my tax return?

If you want to file an amended tax return and you still have time to, then the process of filing the return will depend upon whether you filed your return online or via a paper copy.

What is the process if I filed my tax return online?

If you filed your tax return online, then you can amend your return online as well.

To do this you just need to log into your HMRC online account and select Self-Assessment from the home page.

There is a column with the heading ‘Returns’. This will specify if you have submitted your return and will provide the option to ‘Amend your Self-Assessment Tax Return’.

You will then be presented with further options:

  • Delete a section from your submitted return
  • Add a new section to your submitted return
  • Amend figures already submitted
  • Add/delete a section and/or amend a figure

Once, you have selected the appropriate option for you, then you can amend your return and file the corrected copy.

How do I amend my tax return if I submitted a paper copy?

If you originally submitted a paper copy of your Self-Assessment tax return, then you still have the 12-month amendment window, which will run to 31 October after the filing deadline.

You should be aware that an earlier deadline applies to paper returns.

The process of amending a paper return is to download a new return and update it to the correct figures, and then send it directly to HMRC.

What happens if my amended tax return affects my tax bill?

If the changes to your Self-Assessment Tax Return changes the amount of tax you owe, then you must pay the amount as well as the interest.

In the case that the amount of tax that you owe is reduced and you have already paid it, then you will be eligible for a tax refund.


If you have submitted your Self-Assessment tax return already and believe that you have made a mistake, then be sure to check it as you could potentially be eligible for tax refund.

If you’d like to know any more, please get in touch with us.

I hope that’s useful. If you’d like to see more videos where we answer lots of questions on tax and accounts, take a look at our YouTube page. You can also subscribe for more videos.