What is an income tax calculator?
An income tax calculator estimates your annual tax liability under the Indian Income Tax Act. The income tax calculator computes and compares your liability under both the Old and New tax regimes for FY 2025-26 (Assessment Year 2026-27).
Salaried individuals and business owners must choose between these two tax paths. The calculator factors in your gross annual salary, standard deductions, and eligible Chapter VI-A deductions (such as Section 80C, 80D, HRA exemptions, and home loan interest under Section 24b) to determine the net tax payable under each regime.
New vs Old tax regime: Key Differences
The New Regime is the default tax structure and offers wider tax slabs with lower tax rates, but excludes most deductions. The Old Regime retains higher tax rates across fewer slabs but allows you to claim multiple deductions to lower your taxable income.
- New Regime offers a higher standard deduction of ₹75,000 and full Section 87A rebate for taxable income up to ₹12 lakh.
- Old Regime provides a ₹50,000 standard deduction and allows deductions under 80C, 80D, HRA, and home loan interest.
- Regime comparison is essential to see which structure maximizes your take-home pay.
How does this income tax calculator work?
This calculator computes taxable income by applying standard and chapter deductions based on the selected tax regime. It then applies progressive slab rates to estimate the base tax.
Finally, it factors in Section 87A rebate (if applicable), marginal relief for borderline incomes, and adds the mandatory 4% Health & Education Cess.
T = Sum ( Islab × rslab )
Where –
| T | Total base income tax liability before rebate and cess |
|---|---|
| I_slab | Taxable income falling within a specific slab range |
| r_slab | Applicable tax rate for that specific slab range |
Taxable Income = Gross Income − Standard Deduction − Chapter VI-A Deductions (for Old Regime)
Worked example: Tax on a ₹15 lakh gross salary (New Regime)
Let's trace a taxpayer scenario under the New Tax Regime for FY 2025-26, assuming a gross annual salary of ₹15,00,000. First, we apply the standard deduction of ₹75,000. This reduces the taxable income to: Net Taxable Income = 15,00,000 − 75,00,000 = ₹14,25,000.
Under the FY 2025-26 New Regime slabs, the tax is computed progressively: ₹0 to ₹4,00,000 is taxed at 0% (₹0); ₹4,00,000 to ₹8,00,000 is taxed at 5% (₹20,000); ₹8,00,000 to ₹12,00,000 is taxed at 10% (₹40,000); and ₹12,00,000 to ₹14,25,000 is taxed at 15% (₹33,750). Adding these: Base Tax = 0 + 20,000 + 40,000 + 33,750 = ₹93,750.
Since taxable income exceeds ₹12,00,000, no Section 87A rebate applies. Finally, we add the 4% Health & Education Cess: Cess = 93,750 × 4% = ₹3,750. The total tax payable is: Total Tax = 93,750 + 3,750 = ₹97,500. This leaves a net post-tax income of ₹14,02,500.
For a salaried taxpayer earning ₹15,00,000, the tool projects a net tax of ₹97,500 under the New Regime and compares it side by side with the Old Regime results.
The Friction Section: Regime Lock-Ins and Surcharges
A standard income tax calculator simplifies tax planning into a clean slab calculation. Real-world tax returns involve regime lock-ins and hidden surcharges.
The first hurdle is the regime switching restriction. Salaried taxpayers can choose between the Old and New regimes every year. However, business owners and professionals (with business income) can switch only once in their lifetime. Once they opt out of the default New Regime, they are locked into that choice, making regime selection a high-stakes decision.
The second friction point is surcharges and cess. Surcharges of 10% to 25% apply to high-income earners with taxable income exceeding ₹50 lakh. Additionally, the 4% Health & Education Cess is levied on the tax payable (after rebates), which is often overlooked but adds thousands of rupees to the final tax liability.
Our Take: Why the New Tax Regime is the Default Choice
In our experience, the New Tax Regime has become the superior choice for more than 90% of Indian taxpayers, especially after the standard deduction was raised to ₹75,000 and Section 87A rebate was extended to cover taxable income up to ₹12 lakh. The Old Regime is only beneficial if you have substantial home loan interest (Section 24b), large medical premiums (Section 80D), and maximum 80C investments, totaling ₹3.75 lakh or more in deductions.
We recommend planning your tax regime at the beginning of the financial year. If you choose the Old Regime, automate your investments throughout the year through monthly ELSS SIPs or PPF contributions rather than making frantic lump sum deposits in March. If you choose the New Regime, redirect the money you would have locked up in low-yield tax-saving products into equity mutual funds to grow your long-term wealth.
How to use this income tax calculator
Enter your gross annual income, select your tax regime, and enter your total deductions if you are opting for the Old Regime. The tool immediately displays your net taxable income, base tax, health and education cess, and the total tax payable under both regimes.
To plan your monthly payroll and withholding tax, see the salary calculator. To verify taxes deducted from your vendor payments, check the TDS calculator.
Frequently asked questions
What is standard deduction in Indian income tax?
Standard deduction is a flat amount subtracted from your gross salary before tax slabs are applied. For FY 2025-26, the standard deduction is ₹75,000 under the New Regime and ₹50,000 under the Old Regime for salaried employees and pensioners.
Who is eligible for Section 87A rebate?
Resident individuals with taxable income up to ₹12 lakh under the New Regime are eligible for a tax rebate of up to ₹60,000, making their tax liability zero. Under the Old Regime, the rebate applies to taxable income up to ₹5 lakh.
Can I switch tax regimes every year?
Yes, if you are a salaried employee without business income, you can choose between the Old and New tax regimes every year when filing your ITR. Business owners, however, can only switch regimes once in their lifetime.
What is marginal relief under Section 87A?
Marginal relief protects taxpayers whose income slightly exceeds the ₹12 lakh threshold under the New Regime. It ensures that the tax payable does not exceed the amount by which their taxable income exceeds ₹12 lakh.