My tax return is wrong, what should I do?

My tax return is wrong, what should I do? If you’re concerned that you may have made a mistake on your tax return, don’t panic. There are a few things that you can do to protect…

5 Minute Read

Last Updated: 23rd March 2023

My tax return is wrong, what
should I do?

If you’re concerned that you may have made a mistake on your tax return, don’t panic. There are a few things that you can do to protect yourself from receiving a nasty penalty. Take a look below for GoSimpleTax’s advice:

Amend it Immediately

If you’ve noticed a mistake in your most recent tax return, you have up to twelve months to fix it. Your self assessment should be amended using the same platform through which it was submitted – for example, if you sent it online, the amendment should be made online, and if you did so via the post, your changes should be made by sending hard copies of the corrected pages (each marked “amendment” and labelled with your name and UTR number) to Self Assessment, HM Revenue and Customs, BX9 1AS, United Kingdom.

Write to HMRC

Should the aforementioned twelve months’ leeway have lapsed before you noticed the mistake, you can still contact HMRC to make changes up to four years after the relevant tax year. The letter you send should indicate the year of the tax return you’re amending, the reason for your over or underpayment and the amount thereof.

If you think you’ve overpaid, you also need to explain that you’re claiming for “overpayment relief”, provide proof that a tax payment was made for the relevant period and that you’ve not already tried to claim the amount back, express how you want to be repaid and complete a signed declaration confirming that the details you’ve given are correct and complete to the best of your knowledge.

What To Do Next

You should receive an amended bill within the next three days. If you owe anything extra, you should arrange to pay this immediately.

For future tax returns, consider utilising the GoSimpleTax software or its online tools. This software automatically alerts you of any potential miscalculation or mistake within your tax return, preventing the need for any potential future amendments and protecting you from any resulting fines.

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Blog content is for information purposes and over time may become outdated, although we do strive to keep it current. It's written to help you understand your Tax's and is not to be relied upon as professional accounting, tax and legal advice due to differences in everyone's circumstances. For additional help please contact our support team or HMRC.


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