Advance tax: If you are a salaried taxpayer with other sources of income, like interest income, and your tax liability for the financial year exceeds Rs 10,000 after accounting for the tax deducted by the employer (TDS), you will have to pay advance tax. This has to be paid in the financial year preceding the assessment year in three instalments. The due dates are 15 September, 15 December, and 15 March, and the penalty for not paying is 1% of the due amount per month.
Self-assessment tax: While calculating your tax liability, if you realise that some tax is due after taking into account the TDS and advance tax, then you pay self-assessment tax. This tax is paid in the assessment year before filing the returns.

