If you make an error on your tax return, you normally have 12 months from 31st January after the end of the tax year to correct or amend it. For example, if you filed your 2017/18 online tax return by 31st January 2019, you have until 31st January 2020 to amend it. You can only amend your return after this timeframe if you received your return late (after 31st July).
If you owe more tax or need to pay a penalty because of the mistake, HM Revenue & Customs (HMRC) will notify you how much you need to pay and when and how to pay it. If you believe you are due a refund, you can tell HMRC how you would like to receive it.
If you submitted your tax return online, you can also amend it electronically. And if you chose to file it as a paper copy, there is no need to resend in the whole tax return. Just write to HMRC and attach the pages you want to make corrections to.
If you find preparing your tax return a chore, please feel free to call your local TaxAssist Accountant on 0800 0523 555, and they will be happy to complete it for you. This should ensure your return is accurate and prepared in good time as well as discovering any tax saving opportunities.