Tax

How Income Tax Calculation Works in India

Income tax in India is computed in stages: total your income under different heads, subtract eligible deductions and exemptions, apply the slab structure of your chosen regime, then add cess and adjust for tax already paid. Knowing the structure matters more than memorising the numbers, which change with each Budget.

Last updated2026-06-01· Educational content, not financial advice

Key Takeaways

  • Tax is computed on taxable income, not on your salary or gross receipts.
  • India uses progressive slabs — only the income inside each slab is taxed at that slab's rate.
  • Slab limits, rates, rebates and regime rules are revised in the Union Budget; always check the current year.
  • TDS and advance tax are prepayments, reconciled when you file your return.

Start with the structure, not the numbers

Every year the Union Budget can change slab limits, rates, standard deductions and rebates. What does not change is the sequence of the calculation. If you understand the sequence, you can plug in the current year's figures from the Income Tax Department and follow any calculator's working.

Step 1: Total income under the five heads

Indian tax law groups income into five heads: salary, house property, business or profession, capital gains, and other sources (which includes interest on deposits). Each head has its own rules for what counts and what can be set off. Adding the heads together gives your gross total income.

Step 2: Deductions and exemptions

Depending on the regime you choose, certain amounts are removed before tax is applied — for example specified investments and payments under Chapter VI-A, or a standard deduction against salary. The two regimes differ mainly here: one offers lower rates with fewer deductions, the other higher rates with more. What remains is taxable income.

Step 3: Apply the slabs

India's slabs are progressive. Income up to the first threshold is taxed at the lowest rate (often nil); only the portion above that threshold is taxed at the next rate, and so on. A common misunderstanding is that crossing into a higher slab taxes all your income at the higher rate — it does not. Only the slice inside each slab is taxed at that slab's rate.

Step 4: Rebates, surcharge and cess

A rebate may reduce the tax for taxable income below a specified level. Very high incomes attract a surcharge. Finally, a health and education cess is added as a percentage of the tax. The result is your total tax liability for the year.

Step 5: Reconcile with tax already paid

Tax Deducted at Source (TDS) by your employer or bank and any advance tax you paid are subtracted from the liability. If you paid more, you claim a refund when filing; if less, you pay the balance. See What is TDS? for how the deduction side works.

Where deposits and investments fit

Interest on FDs and RDs is added under 'other sources' and taxed at your slab — read how FD and RD interest is taxed. Some instruments, such as PPF, have specific tax treatment that is part of why people compare them with FDs; our What is PPF? guide explains the concept without quoting current limits.

Why we do not print the slabs here

Because they change. A guide that quotes last year's slab looks authoritative and is quietly wrong. Use the official portal or a current-year calculator for the numbers, and use this page for the logic.

Sources

We reference primary and official sources. Rate- and rule-dependent details must be verified against the latest official information.

Disclaimer: This article is for general education only and is not investment, tax, or financial advice. Statutory rates, tax rules, and regulations change over time — verify current figures with official primary sources before acting.