D Doshi

Hi, My query is about retrospective declaration of foreign interest. For tax year 1, Income + foreign interest will be below the allowance limit. For tax year 2, Income + foreign interest will be marginally above the allowance limit. In both these cases, how do i calculate the tax, if any? Is there a HMRC tax calculator I can use to get this information? I amended my 2022-23 returns and after adding the foreign interest, tax due was still 0. Thank you.