Advance Tax is calculated and paid on which of the following bases?

Advance tax operates on the principle of "Pay as You Earn." Because taxes are paid during the ongoing Tax Year itself (before the year ends and final books are closed), taxpayers must project and estimate their total taxable income across all heads (Salary, PGBP, House Property, Capital Gains, Other Sources) for the entire year. They then calculate the expected net tax liability after reducing eligible deductions, exemptions, TDS, and TCS, paying the resulting tax in scheduled quarterly installments based on those estimates.