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Self Assessment tax returns are stressful enough at the best of times – but what if you’ve filed yours and realise that you’ve made a mistake?
Thankfully, it’s possible to amend your tax return even after it’s been submitted. Read on to find out how.
A Self Assessment error or mistake can be frustrating, but there are things you can do. Perhaps you inputted the wrong figures? Or maybe an HMRC error means you’ve over or underpaid your tax? Read on for what to do now.
It’s possible to make changes if you’ve made a mistake on your Self Assessment tax return after filing it, but there is a time limit. Any changes must be made within 12 months of the normal 31 January filing deadline. For example:
If you miss the deadline, you may still be able to make the changes but you’ll have to write to HMRC.
Download your free in-depth guide to amending your tax return after filing. Get instant access to expert hints and tips at the click of a few buttons.
How you amend your tax return will depend on how you filed it in the first place. Most people now file their Self Assessment returns online.
If you filed online, you can make a tax return correction by following these steps:
If you filed your return on paper, you’ll need to download a new tax return and send HMRC the pages that need correcting.
Write ‘amendment’ on each corrected page, and make sure that you include both your name and your Unique Taxpayer Reference (you can find your UTR on previous correspondence from HMRC). Send it to HMRC at the address found on your Self Assessment paperwork.
If you used third-party software to file your return, you should contact the software provider for help on what to do. If you can't make changes using your chosen software, contact HMRC directly.
If you want to make a tax return correction but have missed the relevant deadline, you should write to HMRC.
When writing to HMRC, make sure you include the following details:
If you think you’ve paid too much tax because HMRC made a mistake, you can usually claim a full rebate. You’ll need to claim within four years of the end of the tax year you’re claiming for. This is called ‘overpayment relief’.
Overpayment relief claims must be made in writing and must:
You must also have documentary proof of tax deducted as you may need to provide this later.
If your claim is successful, a refund will be sent to your bank account within four weeks.
If you’ve paid too much tax because you made a mistake on your tax return, you’ll need to make any amendments within the first year of filing it.
You won’t have to pay a penalty if you’ve taken ‘reasonable care’ to fill out your tax return correctly. However, HMRC can issue penalties if you’ve understated tax or misrepresented your tax liability because you’ve been careless.
Gov.uk explains how penalties are calculated:
Make sure you keep on top of bookkeeping for your business or hire an accountant if you’re not sure of anything.
Making changes to your tax return after filing may mean you’ve underpaid tax. If you’ve made your changes online, you should be able to see the new amount of tax you owe on your Self Assessment tax account within three days.
You’ll also see a deadline for paying the remaining tax. Remember that you may be charged interest.
Your new tax bill may also affect any payments on account you need to pay.
It’s important to tell HMRC about changes to your personal details for Self Assessment as soon as they’ve changed.
If you’ve failed to do this and you need to change the address for your tax return after filing it, make sure you make any corrections following the process above (up to a year after the filing deadline).
You can update your address online if you’ve set up a personal tax account.
Do you have any unanswered questions about changing your tax return? Let us know in the comments.
Photograph 1: Paul Maguire/stock.adobe.com
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