Tax
Taxable income
The portion of your income left after all exemptions and deductions, on which tax is actually calculated.
Taxable income is not your full salary. It is what remains after subtracting exemptions and deductions from your gross income.
Tax slabs apply to this final number, not to your total earnings.
Lowering it legally, through deductions like 80C and 80D, is the whole game of tax planning.
For example
A ₹12L salary minus a ₹50,000 standard deduction and ₹1.5L under 80C gives a taxable income of ₹10L, and tax is charged on that.