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Income tax calculator — both regimes, all the way
The full computation most calculators skip: rebate, marginal relief, surcharge and its marginal relief, cess — for any income level, both regimes, senior-citizen slabs included.
What the calculation includes
- Standard deduction — ₹75,000 (new) / ₹50,000 (old), salary and pension only.
- Slabs — new regime: nil to ₹4L, 5% to ₹8L, 10% to ₹12L, 15% to ₹16L, 20% to ₹20L, 25% to ₹24L, 30% above. Old regime: nil to ₹2.5L (₹3L at 60+, ₹5L at 80+), 5% to ₹5L, 20% to ₹10L, 30% above. Identical in both years — Budget 2026 changed no rates.
- Rebate — new: ₹60,000 up to ₹12 lakh taxable income, with marginal relief just above; old: ₹12,500 up to ₹5 lakh, no relief (the cliff).
- Surcharge — 10% above ₹50 lakh, 15% above ₹1 crore, 25% above ₹2 crore, 37% above ₹5 crore (new regime caps at 25%) — with marginal relief so a rupee over a threshold never costs more than a rupee.
- Cess — 4% health and education cess on tax plus surcharge.
- Monthly TDS — for salary, the annual tax ÷ 12 is what your employer deducts under the regime you declare.
Worked example
Salary ₹18,00,000, below 60, tax year 2026-27, no deductions: new regime — taxable ₹17,25,000 after the standard deduction, tax ₹1,45,000 + 4% cess = ₹1,50,800, ≈ ₹12,600 a month of TDS. Old regime with ₹2,00,000 of deductions — taxable ₹15,50,000, tax ₹2,77,500 + cess = ₹2,88,600. New wins by ₹1.38 lakh. At ₹55 lakh the surcharge appears and its marginal relief matters — try it above.
Edge cases to know
- Special-rate income (capital gains, lottery) is taxed separately and doesn't get the rebate — use the capital gains calculator for that slice.
- Agricultural income above ₹5,000 changes the slab math (partial integration) — not modelled here.
- Senior citizens in the new regime get no higher exemption — the ₹4L nil slab applies to everyone.
- Presumptive freelancers: enter your deemed profit as "business/other" — compute it first with the presumptive calculator.
Related tools
- Old vs new regime comparator — with each deduction capped for you.
- TDS on salary — the monthly view for employees.
- HRA exemption calculator — the biggest old-regime deduction.
Last verified: 18 September 2026 — slabs, rebate, surcharge table and cess cross-checked against the Act's text (s.202, s.156) and post-Budget-2026 coverage; surcharge marginal relief per the Finance Act formula · Reviewed with a practising CA's responses (2 September 2026) · Not tax advice.