I have mistakenly filled in wrong information in the latest self assessment (2023-2024).

Hi, I have mistakenly filled in a tax refund (rebate) I received in 2023 - total £4,678.19 and that it was a tax refund for extra tax I paid in the previous year 2022/23 in the “Tax refunded or set-off” session, and now that the Tax Calculation issued by HRMC shows that I need to pay extra tax for year 2023-2024. 

 The calculation is as follows: 

Income tax overpaid in 2023-2024 (1,844.41) - minus Tax already refunded in the year of £4,678.19 (which should not be included in the 2023-2024, as it was a tax refund for extra tax I paid in the previous year 2022/23) = a total tax due of £2,833.78. What should I do now? Can I request a reassessment from HMRC regarding my latest self-assessment for 2023-2024?

Hi sabrina.lam20201610,
You can log back into your 23/24 return via your Personal Tax Return, remove the £4678.19, then resubmit your return.
Alternatively, contact us by webchat or phone here:
Self Assessment: general enquiries
And we can amend this for you.
Thank you.