C.K. Gupta
For FY 2026-27 the new regime is the default — zero tax up to ₹12 lakh of income — so the calculator you want is one that compares both regimes side-by-side with your actual deductions. The Income Tax Department’s own tool is the most authoritative; TaxGST’s free income tax calculator and the best-known private tools all do old-vs-new comparisons, but they differ on signup friction, deduction detail and marginal relief handling. We compared five, honestly, below. Verified October 2026 · TaxGST.in
October is when salaried taxpayers start their tax planning in earnest: Diwali bonuses land, employers ask for investment proofs, and the third advance-tax instalment is due 15 December 2026. The single most useful five minutes of planning is running your numbers through a good income tax calculator — because the old-vs-new regime answer changes with your HRA, 80C, 80D and home-loan interest. We tested five free calculators so you don’t have to.
What a good income tax calculator must do in FY 2026-27
- Old vs new regime comparison side-by-side — non-negotiable. The new regime (115BAC) is now the default, with zero tax up to ₹12 lakh income; the old regime wins only if your deductions are large enough.
- Real deduction inputs — 80C, 80D, 80TTA/80TTB, HRA, home-loan interest, NPS (80CCD). A calculator that only takes “total income” is a toy.
- Surcharge and marginal relief awareness — high earners need the calculator to not pretend surcharge doesn’t exist.
- No mandatory signup for a basic result — you should get the number before anyone asks for your phone.
- Current slabs — any tool still showing pre-FY25 slabs is disqualified.
The five calculators, compared honestly
1. TaxGST Income Tax Calculator — best no-fuss free option
Our own free income tax calculator: enter income and deductions, get an instant old-vs-new comparison with the FY 2026-27 slabs. No account, no email gate, unlimited use.
Pros: genuinely free with zero signup friction; built for the current FY; sits next to our income tax guides and deduction explainers so you can act on the result. Cons: it is a focused tax-computation tool, not a full financial-planning suite — if you want portfolio-linked projections, a wealth app fits better.
2. Income Tax Department calculator (incometax.gov.in) — most authoritative
The official calculator on the e-filing portal, maintained by the tax department itself. Slabs and rebate logic are definitionally correct.
Pros: the reference implementation — if a private tool disagrees with this one, trust this one; free. Cons: utilitarian interface; the most useful version sits behind portal login; not designed for quick “what-if” playing with deduction combinations.
3. ClearTax income tax calculator — most detailed for complex cases
One of India’s oldest tax platforms; its calculator handles the full deduction stack and special incomes, and it plugs into their filing flow if you decide to file there.
Pros: depth — good for taxpayers with capital gains, rental income and multiple deduction heads; kept current. Cons: expect signup nudges and upsell prompts around the result; the free calculator is partly a funnel into paid filing.
4. Groww income tax calculator — simplest for first-time users
The investing app’s calculator is deliberately minimal: a few inputs, a clean result, built for users who find tax portals intimidating.
Pros: the fastest path from “I’ve never done this” to a regime answer; mobile-friendly. Cons: limited deduction granularity — if your 80D + HRA + home-loan stack is what decides your regime, a simpler tool may not capture it.
5. ET Money / Paisabazaar calculators — fine, with an agenda
Fintech-platform calculators that are accurate enough for a first estimate and sit inside apps that also want to sell you investments or loans.
Pros: quick, free, decent for a rough regime check. Cons: the result page is advertising-adjacent — expect product recommendations alongside your tax number; verify any borderline result on an authoritative tool before acting.
Quick comparison table
| Calculator | Free | No signup needed | Old-vs-new compare | Best for |
|---|---|---|---|---|
| TaxGST | Yes | Yes | Yes | Quick honest answer |
| Income Tax Dept | Yes | Partial | Yes | Authoritative check |
| ClearTax | Yes | No | Yes | Complex incomes |
| Groww | Yes | Yes | Yes | Beginners |
| ET Money / Paisabazaar | Yes | Varies | Yes | Rough estimate |
How to use the result: a 5-minute October routine
- Run your real numbers — salary, bonus, rental income, capital gains so far this year, plus 80C/80D/HRA you will actually claim. Note which regime wins and by how much.
- Tell your employer now. Submit Form 12BB investment proofs before the Diwali-bonus payroll runs so TDS is cut at the right rate — otherwise you wait for a refund.
- Check advance tax. If salary TDS won’t cover your total liability (bonus, capital gains, freelance income), the third instalment — 75% of total tax cumulatively — is due 15 December 2026. Shortfalls attract interest under Sections 234B and 234C. The full deadline list lives on the compliance calendar hub.
- Re-run in December after the bonus actually lands; regime choice for FY 2026-27 can still be optimised before the financial year ends.
Frequently asked questions
Which is the best free income tax calculator in India for FY 2026-27?
For authority, the Income Tax Department’s own calculator. For a fast, no-signup old-vs-new comparison, TaxGST’s free income tax calculator. For complex incomes with capital gains and multiple deductions, ClearTax’s is the most detailed free option.
Do income tax calculators handle the new regime’s ₹12 lakh rebate?
Any calculator current for FY 2026-27 should — under Section 87A, resident individuals pay zero tax up to ₹12 lakh of taxable income in the new regime (₹12.75 lakh for salaried, counting the standard deduction). If a tool doesn’t show this, it’s outdated.
Can I rely on a calculator instead of a CA?
For regime choice and planning, yes — calculators are accurate for standard salary and deduction cases. For business income, capital-gains set-offs, foreign assets or notices, get professional advice. Our GST and tax consultants handle the complicated end.
Old regime or new regime — how do I decide?
Run both with your actual deductions. Rough rule of thumb: if your total deductions (80C + 80D + HRA + home-loan interest + NPS) comfortably exceed ~₹4–5 lakh, the old regime often wins; below that, the new regime usually does. But “rough” is why you run the numbers.
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