I agree with S4mmyhelp. For 2022/2023 tax year I had no other taxable income besides what I earned through PAYE. When I log into my account and browse to
https://www.tax.service.gov.uk/tax-you-paid/2022-2023/right-amount it shows: "You paid the right amount of Income Tax for 6 April 2022 to 5 April 2023" The tax amount matches the amount on my P60 for Tax year to 5 April 2023. However when I completed my Self Assessment in calculated it said I owed £2.00 in tax. I have paid the £2 but I am puzzled why the self-assessment calculated the extra £2.00 tax. I have always thought any tax code e.g xyx meant a personal tax allowance of £xyx9.00. I think the tax tables show the tax-free amount are based in £xyx9.00.