Hi,
If the figures entered in your tax return are in the correct boxes, including tax deducted, the calculation will be correct. You may find that in addition to the tax owed for the tax year, sa 2023 to 2024, you are being asked to make a payment in advance for 2024 to 2025. This is know as a payment on account.
Please have a look at the guidance on payments on account at:
Understand your Self Assessment tax bill
For a more detailed answer to a personal question of this nature, you would need to contact our Self Assesment team.
Self Assessment: general enquiries
Thank you.