Difference between Tax calculation @ HMRC tax calculator & Self-assessment

I am using the same numbers in both the portals. My employer has deducted tax exactly the same amount which is being reflected in the HMRC tax portal. However, when I am trying to fill the self-assessment, it's showing that I still have to pay more. I am confused as to how to take it forward. Which calculation is correct and how should I move forward?

If you're referring to https://www.gov.uk/estimate-income-tax - well, it prominently says it is an *estimate*, not a final figure. Self Assessment determines what you actually pay. You could: * talk to HMRC web chat self assessment support * talk to a professional tax adviser * if you personally feel happy to share further details of your Self Assessment calculation with this anonymous Internet forum, you might get help in understanding it from community members

Hi,

We would need to review your calculation to check why a balance is showing as due. If you submit your Self Assessment tax return and allow 3 working days to process and then contact HMRC we can review this for you. If an amendment is needed this can then be done.

Details of how to contact HMRC at:

Self Assessment: general enquiries

Thank you.