Income tax calculator FY 2026-27: every line explained

What the calculator answers

The income tax calculator takes one number, your taxable income, and returns the tax on it for FY 2026-27 (AY 2027-28) under either regime. It shows how that tax is built up, the effective rate, and what the other regime would charge on the same income. It is a slab calculator, so it is useful for checking the tax line on a payslip or Form 16, or for seeing what a raise does to your bill.

The inputs

There are only two:

• New regime / Old regime. A toggle. The new regime is the default under the law since AY 2024-25, and it is the default here.
• Taxable income, after deductions (₹). It starts at ₹15,00,000. "After deductions" matters: the calculator does not subtract the standard deduction, section 80C, HRA or anything else for you. If you are salaried, take gross salary and subtract ₹75,000 (new regime) or ₹50,000 (old regime) before entering it. The salary calculator does that step for you if you would rather start from CTC.

The outputs, line by line

The two headline boxes are Total tax payable and Effective rate (tax as a share of the income you entered). Below them, "How it is computed" breaks the total into three rows:

1. Tax at slab rates, after rebate. Slab tax minus the §87A rebate, with marginal relief already applied where it bites.
2. Surcharge. Zero below ₹50 lakh.
3. Health & education cess (4%). Charged on the first two rows combined.

A box called "Which regime costs less?" then prints both regimes' totals and marks the cheaper one. A donut chart shows the same three parts.

The slabs as coded for FY 2026-27:

The §87A rebate is up to ₹60,000 when taxable income is ₹12 lakh or less under the new regime, and up to ₹12,500 at ₹5 lakh or less under the old one.

Worked example: ₹15 lakh of taxable income

With the default ₹15,00,000 and the new regime selected, the calculator returns:

• Tax at slab rates, after rebate: ₹1,05,000 (5% of ₹4 lakh, 10% of ₹4 lakh, 15% of ₹3 lakh; no rebate, because income is above ₹12 lakh)
• Surcharge: ₹0
• Cess: ₹4,200
• Total tax payable: ₹1,09,200, an effective rate of 7.28%

Flip to the old regime and the same ₹15,00,000 costs ₹2,73,000 (₹2,62,500 plus ₹10,500 cess), or 18.2%.

How to read the regime comparison

That ₹1.64 lakh gap is not the real choice, and the note under the calculator says so. Both figures use the same taxable income, but the old regime allows deductions the new one does not, so your old-regime taxable income is normally lower. To compare properly, open the old vs new regime calculator. It starts from gross salary and solves for the deductions at which the two regimes tie. At ₹15,75,000 of gross salary, which is ₹15 lakh of new-regime taxable income after the ₹75,000 standard deduction, the new regime's tax is the same ₹1,09,200, and the old regime only matches it with ₹5,62,500 of deductions beyond its own standard deduction. Our old vs new regime comparison for FY 2026-27 runs that break-even at seven salary levels.

The two cliffs, and where relief applies

The rebate creates a cliff in both regimes, but the calculator treats them differently, because the law does.

Under the new regime, marginal relief means the tax before cess cannot exceed the income above ₹12 lakh. When it applies, a dashed note appears: "Marginal relief applied at the §87A rebate threshold". It runs out at about ₹12,70,600, where ordinary slab tax becomes the smaller figure. The old regime has no such relief: ₹10,000 more income above ₹5 lakh costs ₹15,080.

Surcharge works the same way at each threshold. At ₹51,00,000 under the new regime, slab tax is ₹11,10,000 and a straight 10% surcharge would be ₹1,11,000. Relief cuts it to ₹70,000, so the total is ₹12,27,200: tax at ₹50 lakh plus no more than the extra ₹1 lakh of income, then cess. Surcharge rises to 15%, 25% and 37% above ₹1 crore, ₹2 crore and ₹5 crore, capped at 25% under the new regime.

What the calculator does not do

• It does not compute deductions. Standard deduction, section 80C, HRA and home-loan interest all have to be taken off before you enter the figure. The HRA post shows how large the HRA piece can be.
• No capital gains. Short-term and long-term gains taxed at special rates are outside it, and the §87A rebate cannot be set against them. For salary plus gains in one return, use the salary and capital gains calculator.
• Old-regime slabs are for under-60s. The basic exemption is ₹3 lakh at 60–79 and ₹5 lakh at 80 and above, and the calculator does not switch slabs by age.
• Rates change with each budget. These are the FY 2026-27 figures as coded; check them against the Income Tax Department before filing.

Where to go next

If you are starting from an offer letter rather than a payslip, the CTC to in-hand walkthrough shows the steps before taxable income. The guide to choosing your tax regime covers what the choice locks in. Then come back to the income tax calculator with your own taxable income. This is an estimate for planning, not tax advice.