How income tax actually works
India's income tax is slab-based: different slices of your income are taxed at different rates, and only the slice above each threshold faces the higher rate. Earning ₹13 lakh does not mean all ₹13 lakh is taxed at the top rate — the first slices are taxed at lower or zero rates, and only the portion above each cutoff moves up. This marginal system is the single most misunderstood fact in personal finance.
Your gross salary is also not your taxable income. Subtract the standard deduction (₹75,000 under the new regime), exempt allowances like HRA in the old regime, and chapter VI-A deductions such as 80C — what remains is the figure slabs apply to. Every tax plan is really about shrinking that taxable figure legally.
Old regime vs new regime
The new regime taxes income at lower slab rates but removes most exemptions — no HRA, no 80C, no 80D. It suits people with few deductions: young renters without a home loan, or anyone who prefers simplicity. It is the default regime, and salaried income up to about ₹12.75 lakh effectively pays no tax after the standard deduction and rebate.
The old regime keeps higher slab rates but preserves the full deduction toolkit: HRA, 80C (₹1.5 lakh), 80D health insurance, NPS 80CCD(1B), and home-loan interest under section 24(b). It usually wins when your total deductions exceed roughly ₹4–5 lakh — common for homeowners with HRA, 80C, and 80D combined. The only correct answer is to compute both every year, because salary changes and rule tweaks flip the winner regularly.
- New regime: lower rates, almost no deductions, simpler
- Old regime: higher rates, full deductions — wins with ~₹4–5L+ of claims
- Compare both regimes every financial year before filing
- Salaried employees can switch regimes year to year (with conditions)
Deductions that actually move the needle
Section 80C (₹1.5 lakh limit) is the workhorse: EPF contributions, PPF, ELSS funds, children's tuition fees, and home-loan principal all count — most salaried people fill half of it without trying. Section 80D covers health-insurance premiums (up to ₹25,000 for self/family, ₹50,000 for senior-citizen parents), and section 80CCD(1B) adds an extra ₹50,000 for NPS on top of 80C.
Beyond those, HRA exemption helps renters in the old regime (minimum of actual HRA, 50%/40% of basic, or rent minus 10% of salary), section 24(b) allows up to ₹2 lakh of home-loan interest against let-out or self-occupied property, and the standard deduction applies automatically. These five — 80C, 80D, NPS, HRA, home-loan interest — cover 90% of realistic tax savings for employees.
A real example: ₹12 lakh salary
Take a salaried employee earning ₹12 lakh with ₹1.5 lakh in 80C (EPF + PPF), a ₹25,000 health-insurance premium, and ₹50,000 in NPS. Old-regime taxable income: roughly ₹12,00,000 − ₹50,000 (standard deduction) − ₹1,50,000 − ₹25,000 − ₹50,000 = about ₹9.25 lakh, taxed at old-regime slabs.
Under the new regime the same person claims only the ₹75,000 standard deduction, leaving about ₹11.25 lakh taxable — but at lower slab rates with rebate mechanics. Running both side by side takes two minutes with an income-tax calculator and reveals the cheaper option instantly. Never assume last year's winner still wins.
Plan across the year, not in March
The March scramble — random ELSS purchases and insurance bought for receipts rather than needs — is how people end up with unsuitable products. Instead, declare planned 80C/80D investments to your employer in April so TDS spreads correctly, automate monthly PPF or ELSS contributions, and file proofs as they arrive.
Do a 15-minute review each quarter: July (confirm TDS matches Form 26AS/AIS), October (adjust for raises), January (final regime choice and top-ups), March only for verification. And avoid the big three mistakes: never rechecking your regime, buying insurance purely for 80C, and ignoring AIS mismatches until a notice arrives.
- April: declare planned deductions to employer for correct TDS
- July & October: reconcile TDS with Form 26AS/AIS
- January: final old-vs-new comparison and top-ups
- Separate insurance from investing; file before the July deadline
New-regime slabs with a worked calculation
Under the new regime slabs (0–₹4 lakh nil, ₹4–8 lakh at 5%, ₹8–12 lakh at 10%, ₹12–16 lakh at 15%, and higher bands beyond), a taxable income of ₹11.25 lakh attracts roughly ₹20,000 on the second slab (4,00,000 × 5%) plus about ₹32,500 on the third (3,25,000 × 10%) — about ₹52,500 before cess and rebate. In practice the rebate wipes this out for incomes up to about ₹12 lakh (₹12.75 lakh for salaried employees after the ₹75,000 standard deduction), which is why most mid-salaried employees owe nothing in the new regime.
Contrast the old regime on ₹9.25 lakh taxable: roughly ₹12,500 on the ₹2.5–5 lakh band (2,50,000 × 5%) plus about ₹42,500 on the ₹5–9.25 lakh band (4,25,000 × 10%) — about ₹55,000 plus 4% cess, or roughly ₹57,200. Neither figure includes surcharges or marginal relief, so treat this as a comparison framework rather than your exact liability — then run your own numbers through an income-tax calculator with current-year slab and rebate rules before choosing.
- ₹11.25L taxable (new regime): ~₹52,500 slab tax before cess and rebate
- Rebate zeroes new-regime liability up to ~₹12L (₹12.75L salaried with standard deduction)
- ₹9.25L taxable (old regime): ~₹55,000 + 4% cess ≈ ₹57,200
- Always recompute with the current year's official slabs before filing
HRA exemption: three worked cases
HRA exemption (old regime only) is the minimum of three figures: actual HRA received, 50% of basic salary for metro cities (40% elsewhere), and rent paid minus 10% of basic. Take basic pay of ₹7.2 lakh a year with ₹3 lakh HRA received. Paying ₹20,000/month rent (₹2.4 lakh/year) in Mumbai gives min(3,00,000, 3,60,000, 2,40,000 − 72,000) = ₹1,68,000 exempt — the rent-minus-10% leg binds.
Raise that Mumbai rent to ₹30,000/month (₹3.6 lakh/year) and the exemption jumps to min(3,00,000, 3,60,000, 2,88,000) = ₹2,88,000. But the same ₹30,000 rent in a non-metro city gives min(3,00,000, 2,88,000, 2,88,000) = ₹2,88,000 — here the 40%-of-basic ceiling binds instead. Lesson: in metros, higher rent directly raises exemption until HRA caps it; outside metros, the 40% ceiling caps you early, so oversized rent buys no extra tax benefit. Keep rent receipts and the landlord's PAN for annual rent above ₹1 lakh.
- Formula: min(actual HRA, 50%/40% of basic, rent − 10% of basic)
- Metro, ₹20k rent on ₹7.2L basic: ₹1,68,000 exempt (rent leg binds)
- Metro, ₹30k rent: ₹2,88,000 exempt; non-metro, same rent: ₹2,88,000 (40% ceiling binds)
- Landlord PAN mandatory for yearly rent above ₹1 lakh; keep receipts monthly
Tax mistakes that trigger notices
The most common notice-generator is ignoring the Annual Information Statement: your bank reports ₹60,000 of FD interest while you declare ₹40,000, and the computer flags the ₹20,000 gap automatically. Interest on savings accounts (taxable beyond the ₹10,000 section 80TTA deduction, ₹50,000 under 80TTB for seniors), second-employer Form 16s, and freelance receipts all feed the same mismatch engine.
The other repeat mistakes: forgetting to pay advance tax when non-TDS income (rent, capital gains, freelance) pushes extra liability above ₹10,000 a year, which draws 234B/234C interest; and mixing up the filing deadline with the regime deadline — salaried staff can usually switch regimes yearly when filing on time, but a belated return locks you out of choices and carry-forward losses. File early, reconcile AIS/TIS with Form 26AS first, and pay advance tax in the June–September–December–March instalments instead of one March panic.
- Reconcile AIS/TIS with Form 26AS before filing — declare every rupee of interest
- Advance tax applies above ₹10,000 extra liability; missed instalments draw interest
- Belated returns restrict regime choice and loss carry-forward — file on time
- Never buy ULIPs or endowment plans in March purely for 80C receipts