Extra tax for self-assessment

In Jan 2024, for tax year 2022-23, if I just put P60 & P11D from one employment into the self-assessment & nothing else, the tax calculator return that "Income Tax due after allowances and reliefs" amount is slightly greater than the "tax deducted" amount from P60. The return showed that I owed HRRC that difference. Why the difference? Have I put anything wrong in the self-assessment? My employer did not file the correct amount in P60? Extra tax required for self-assessment for employment income & benefit?

Hi,

While it could be that the figure you entered from your P11D differed from the one present in your tax code for the year, there are a number of other possible explanations. To allow us to review this for you, please contact our Self Assessment team.

Self Assessment: general enquiries

Thank you.

I have tried the Twitter and Phone support before opening a post here. Both failed to explain the difference. The Twitter support said the HMRC tax returns calculator would work out for me. The Phone support said the same and asked me to seek for a tax advisor & urged me to close the call, after waiting for the Phone support more than 1 hour by the phone. The details are as below: (A) Pay from all employments: £45,150.00 (according to P60) (B) plus benefits and expenses received: £1,932.00 (according to P11D) (C) Income Tax due after allowances and reliefs: £6,902.40 (according to HMRC Tax Return calculator) (D) Income Tax due: £6,902.40 (according to HMRC Tax Return calculator) (E) Tax deducted From all employments, UK pensions and state benefits: £6,609.18 (according to P60) (F) Total tax deducted: £6,609.18 (according to P60) (G) Total Income Tax due: £293.22 (according to HMRC Tax Return calculator) I can understand how HMRC calculate the field (C)/(D) from field (A) and (B). Why the difference between field (C)/(D) and field (E)/(F)? Why P60 does not match HMRC Tax Return calculator? Have I put anything wrong in the self-assessment? My employer did not file the correct amount in P60? Extra tax required for self-assessment for employment income & benefit?

The Final Tax code is 1193LM1, according to P60. How can I check which tax code used for the self-assessment tax return?

Hi L,
We are sorry to hear you've experienced issues finding an answer to your query.
There are a number of possible explanations as to why the overall tax due is more than the tax collected in-year by your employer.
 For example, it could be that the expenses you've entered in your tax return are different to those that were present in your tax code through the year, or it could be that your employer operated the wrong code.
To give you the correct answer, we would need to check your record and return.
Please contact us be webchat or phone here:
Self Assessment: general enquiries
To allow us to do this.
Thank you. 

Hi L,
Your tax code is your standard amount of tax free allowances for the year, plus or minus any expenses, benefits or deductions you are actively claiming through the tax year.
When you file your tax return at the end of the tax year, the standard amount of tax free allowances is again applied, while you confirm yourself any expenses, benefits or deductions you want to apply to your calculation.
If the expenses, benefits or deductions in your code match the amounts you apply to your calculation, then the same tax code will effectively be used in your return.
Thank you,