High Income Child Benefit - Tax calculated far higher than total Child Benefit received

I am paid roughly £51,000 after tax, through a job that pays tax through PAYE. This is my only income. This is the first year I have gone over the 50,000 threshold for HICBC. I entered the details into the self assessment form as instructed, however now received notification that I owe over £4,600 in taxes, more than double the total child benefit I received. The details just say "Balancing Payment" with no further explanation other than "Tax". There is clearly a mistake because I already paid tax via PAYE. How do I correct this as I believe I owe less than £200? What is the process to request a review? I can see an option to amend the self assessment but I cannot see where I have made a mistake.

I also have this! My situation is ~55k p/a ~Child Benefit EXACTLY £2291 Somehow I owe £3667 to be paid by Jan 31st. This cannot have anything to do with income tax as they are all handled on PAYE and I can see on every payslip that I have been taxed what looks like an appropriate amount, and worth noting that this would be handled through PAYE code adjustments if there was an error and not in self assessment repayments as far as I know. Your situation makes absolutely zero sense unless you had a windfall from some investment (which you would have had to declare on the form anyway for it to factor in!). This process is infuriating every year, if HMRC would actually publish the workings of there calculations in full it would entirely resolve this.

OK so I resolved mine, it was due to myself having selected that I was repaying student loans, when i had paid them off before this tax year. Worth checking if you selected this option in error.

I suspect what might have happened is that you were given a "wrong" tax code which meant you were paying less tax each month. The calculation from self-assessment will show how basic and higher rate taxes are applied to your total income. It takes your total income then calculates how much tax should have paid, then compares that with how much tax was actually paid. The difference then determines whether you owe any tax.

Hi bkbkbkbk

We would need to access your record to check why the balance outstanding larger than expected.
You can contact HMRC at Self Assessment: general enquiries

Thank you

Thanks - I think I might have found the issue - which is that I used an incorrect figure (pre-pension-pre-tax) for one of the boxes rather than post-pension-pre-tax. I've submitted an amendment so hopefully that resolves it.

I’m having the same issue. If I don’t include benefits from my p11d the figure is correct, if i do include them apparently I owe £2800 plus another balancing payment by July 2025. Honestly wish I’d just cancelled this benefit the moment I went over the £50k threshold. Also had to pay more than I received last year and this is all in the context of my tax code being adjusted once my p11d was filed in April anyway so surely that would be the way any underpayment for tax was dealt with?