Old vs New Tax Regime Comparator

How this works

The new regime’s tax is flat with respect to deductions, because it barely allows any. The old regime’s tax falls as you claim more. Two lines, one crossing. The crossing is the only number that decides anything.

The tool computes both, then binary-searches for the deduction total at which the old regime’s tax drops to meet the new regime’s. Old-regime tax is monotone non-increasing in deductions, so the search is safe and converges in sixty iterations.

Three outcomes are possible, and the tool names which one you are in:

• A reachable breakeven. You get the number, and the gap between it and what you currently claim. That gap is the decision.
• Zero. The old regime already wins with no optional deductions at all, usually because of the age-based exemption or an employer NPS contribution.
• Unreachable. At some incomes the old regime’s 30% band starts too early to ever recover, and no level of deduction closes the gap. The tool says so plainly instead of drawing a crossover that does not exist.

What most comparators skip

Marginal relief. Two places, and leaving either out produces visibly wrong numbers.

The 87A cliff in the new regime: the rebate covers tax entirely up to ₹12,00,000 of taxable income and then stops dead. Earning ₹10,000 past it would cost ₹61,500 without relief. Relief caps the tax at the rupees earned beyond the ceiling, giving ₹10,000 plus cess.

Surcharge thresholds: the same logic at ₹50,00,000, ₹1,00,00,000, ₹2,00,00,000 and, old regime only, ₹5,00,00,000. One rupee past ₹50,00,000 would otherwise trigger roughly ₹1,31,000 of surcharge. Relief reduces it to a few rupees.

The surcharge cap difference. The new regime tops out at 25%. The old regime’s 37% band still exists. At very high incomes that is the whole comparison, and it is why the effective top rate differs between the two regimes by several points.

The old regime’s 87A cliff has no relief at all. Cross ₹5,00,000 of taxable income by ten rupees and tax jumps by about ₹13,000. That is genuinely how the section is drafted. It is worth knowing before you decide to claim one rupee less of 80C.

Inputs explained

• Gross salary - before deductions, excluding employer PF and gratuity. If you only know your CTC, run it through the CTC calculator first.
• Age band - only the old regime varies by age: ₹3,00,000 exemption from 60, ₹5,00,000 from 80. The new regime uses ₹4,00,000 for everyone.
• 80C - capped at ₹1,50,000, and your own EPF contribution counts toward it, so include it.
• HRA exemption - the exempt portion under section 10(13A), not the HRA you receive. It is the least of actual HRA, 50% of basic in a metro or 40% elsewhere, and rent paid minus 10% of basic.
• 80CCD(2), employer NPS - the one meaningful deduction both regimes allow, which makes it disproportionately valuable in the new one.
• Other deductions - LTA, 80E education loan interest, 80G donations, 80TTA savings interest, professional tax.

Reading the chart

The flat line is the new regime. The falling line is the old regime as deductions rise. The dashed green marker is the breakeven; the dotted accent marker is where you currently sit. If your marker is left of the breakeven, the new regime wins, and the distance between them tells you how much more you would have to find.

Sources

• Income-tax Act, 2025 - in force 1 April 2026, replacing the Income-tax Act, 1961, verified 2026-08-28
• Published slab, surcharge, cess and section 87A figures for tax year 2026-27, cross-checked across multiple sources, verified 2026-08-28
• Section 115BAC surcharge cap of 25% under the new regime, against 37% under the old, verified 2026-08-28

Limitations

• Estimates, not a filing. Use them to choose a regime, not to compute a liability.
• No capital gains. Sections 111A, 112A and 115AD cap surcharge at 15% on those, and on domestic dividends. Entering capital gains as ordinary income will overstate surcharge at the top end.
• The 80CCD(2) cap is not enforced here. It is 14% of basic in the new regime and 10% in the old, and this app does not know your basic. The CTC calculator applies it properly.
• Salaried assumptions. The standard deduction is applied whenever salary is above zero. Business and professional income has different rules, including restrictions on switching regimes year to year.
• It cannot tell you whether you will actually invest. The breakeven is only useful if you are honest about the deductions you will genuinely claim, rather than the ones you could.

Disclaimer

This tool is provided as is, with no warranty of any kind, express or implied, including no warranty of merchantability, fitness for a particular purpose, accuracy, completeness or currency. There is no guarantee that the slabs, rates, limits or rules encoded here are correct or current.

These are estimates from a personal engineering project. This is not tax, legal or financial advice, and no professional or advisory relationship is created by using it. Your actual liability depends on your full financial position, your employer’s payroll policy, the declarations you file and provisions this tool does not model.

Verify anything that matters with a qualified chartered accountant or tax adviser before you act on it, and do not use these figures to negotiate, plan or file. To the fullest extent permitted by law, no liability is accepted for any loss or damage arising from use of this tool or reliance on its output. Use entirely at your own risk.