Self assessment tax calculation

First time filling out the self assessment return, as my income has gone over £100k a bit for year 2022-2023 (by about £1,800). The calculation shows I need to pay £364 tax but my income is all PAYE salary (except c.£130 saving account interest), so I'm not sure why extra tax needs to be paid. I would be grateful for any help/guidance.

Hi syu0402,

When you earn over £100,000 your Personal Allowance is reduced by £1 for every £2 that you go over.
If your tax code was not reduced during the tax year with an estimated income over £100,000 you will have additional tax to pay.

Thank you,