Old vs new tax regime: how to actually choose

The baseline, computed

These figures come from the same engine as our income tax calculator — new-regime slabs with the ₹75,000 standard deduction, the 87A rebate with marginal relief, and 4% cess. The old-regime column assumes only its ₹50,000 standard deduction, which is precisely the point: it shows what the old regime costs before your deductions start working.

Where the old regime starts winning

Deductions reduce old-regime tax at your marginal rate — 31.2% including cess once you are in the 30% slab. So the deduction pile needed to close the gap is roughly the gap divided by 0.312. At ₹16 lakh, closing a ₹1,75,500 gap takes about ₹5.6 lakh of deductions beyond the standard one. At ₹25 lakh, about ₹8 lakh. Treat these as rough thresholds, not gospel — surcharge, HRA mechanics and the 87A cliff all bend the line — and then verify your own case in two minutes on the calculator, which shows both regimes side by side for any income.

What realistically gets you to ₹5–6 lakh? Not 80C alone — it caps at ₹1.5 lakh. The old regime’s serious artillery is the combination: 80C at ₹1.5 lakh, home-loan interest up to ₹2 lakh on a self-occupied house, employer NPS under 80CCD(2), ₹50,000 of your own NPS under 80CCD(1B), health premiums under 80D, and — the big variable — HRA if you pay substantial rent in a metro. A renter with a home loan and disciplined 80C can clear the threshold. A young employee with a PF deduction and little else almost never can.

The ₹12 lakh cliff deserves respect

The 87A rebate makes taxable income up to ₹12 lakh tax-free in the new regime, and marginal relief smooths the edge just above it. This changes behaviour worth money: if your taxable income lands slightly above the threshold, an employer-NPS contribution — one of the few deductions the new regime allows — can pull you under it, converting a few thousand rupees of contribution into a five-figure tax saving. People near the cliff should model this precisely rather than guess; the calculator flags marginal relief when it applies.

Note also what the rebate did to the old regime’s constituency: below ₹12 lakh there is essentially no deduction pile that makes the old regime competitive with zero. If you earn under ₹12 lakh and someone is selling you a tax-saving product “for the deduction”, the deduction is worth nothing to you in the new regime — which is now the sharper question to ask the seller.

Choose annually, not once

Salaried taxpayers without business income can switch regimes every year at filing time. That means this is not an identity, it is an annual comparison: the year you prepay your home loan and lose the interest deduction, the old regime may stop making sense; the year you move to a rented flat in Mumbai, it may start again. Put a fifteen-minute recheck in your March routine — compute both regimes on your actual numbers, pick the cheaper, and tell your employer’s payroll before the declaration window closes so your TDS follows the right regime from April instead of being reconciled at filing.

And a candid boundary: the calculator tells you which regime is cheaper on the numbers you enter. Whether an insurance-heavy 80C portfolio was worth buying in the first place, or whether your salary structure should be renegotiated for the new regime, are advice questions — a fee-only planner is the right person for those, precisely because they earn nothing from what you buy.