How a Fixed Deposit Grows Your Money
A fixed deposit (FD) is a lump sum parked with a bank at a locked rate for a fixed tenure, anywhere from 7 days to 10 years. The rate at booking never changes, which is the product's whole appeal: you know the maturity value to the rupee before you sign. Banks in India have credited retail FD interest quarterly as the standard practice since the late 1990s, and this calculator defaults to that convention.
Two numbers decide whether a deposit is worth booking: the maturity value and the total interest earned. This calculator reports both, plus the effective annual yield that accounts for compounding. That third figure matters because the compound interest calculator math inside every FD rewards reinvested interest — each quarterly credit starts earning its own interest immediately.
Because the rate is fixed, an FD behaves like a bond with zero price risk; the trade-off is liquidity and inflation risk instead. The ₹100,000 default deposit at 7.1% for 36 months becomes ₹123,507.50 regardless of what markets, elections, or policy rates do in between. Predictability of that kind is rare in finance, and it is why time deposits remain one of the largest pools of household savings in India.
The Maturity Formula Behind the Result
The engine is M = P × (1 + r/n)^(n × t): P is your deposit, r the annual rate as a decimal, n the compounding periods per year, and t the tenure in years. Quarterly compounding sets n = 4, so the per-period rate is the card rate divided by four and applied once every three months. Monthly, half-yearly, and yearly options simply change n — nothing else in the formula moves.
Running the defaults: ₹100,000 × (1 + 0.071/4)^12 = ₹123,507.50 after 36 months, of which ₹23,507.50 is interest. Payout modes drop the exponent entirely — a monthly income deposit earns simple interest at P × r ÷ 12, or ₹591.67 per month on the same balance, because the interest leaves the account instead of compounding inside it.
The effective yield line annualizes what you actually earned: 7.29% here versus the 7.1% card rate. Tenure and frequency both push that gap wider, which is why comparing card rates across banks is a weak basis for a decision. The effective interest rate calculator runs the same annualization math for any nominal-rate product you might hold instead.
Cumulative vs Monthly and Quarterly Payouts
A cumulative FD reinvests every interest credit, so the deposit compounds until maturity — the right structure when growth is the goal. A non-cumulative FD pays interest out monthly or quarterly and returns only the principal at the end. Same bank, same rate, materially different outcomes, because the payout version forgoes every bit of compounding.
On ₹100,000 at 7.1% for 3 years, cumulative interest totals ₹23,507.50 while payout interest totals ₹21,300.00 — a ₹2,207.50 gap. In payout mode that translates to ₹591.67 every month or ₹1,775.00 every quarter, cash you can spend without touching the principal. Retirees often run several payout FDs timed to different months so income lands evenly across the year.
The break-even question is what you would do with the payouts. Redirected into an instrument paying above the FD rate, payouts can win; left idle in a savings account at 3%, they lose comfortably to cumulative. An annuity payout calculator extends the same income-versus-growth trade-off to insurance products that guarantee payments for life rather than a fixed tenure.
Senior Citizen Rates: The Extra 0.50% Compounds
Nearly every Indian bank adds 0.25% to 0.75% to card rates for depositors aged 60 and above, with 0.50% the most common increment. The bonus applies automatically once age proof is on file, and several banks run special senior tenures with larger increments on longer terms. The calculator adds the bonus to the card rate before any compounding math runs.
The increment looks trivial and compounds into real money. On ₹100,000 at a 7.1% card rate for 36 months, the senior rate of 7.6% matures at ₹125,340.15 versus ₹123,507.50 — ₹1,832.65 extra from half a percentage point. Over 60 months the gap reaches about ₹3,533, and on payout deposits it lifts monthly income from ₹591.67 to ₹633.33.
Joint deposits count the first holder's age for the bonus at most banks, so naming the senior parent first on a family deposit captures the increment legitimately. Because the senior bonus sits inside the same compounding math, comparing offers in APY calculator terms — effective yield rather than card rate — keeps cross-bank comparisons honest.
Choosing a Tenure: Where FD Rates Tend to Peak
Large-bank rate cards usually form a hump: rates climb from 7-day lows, peak somewhere between 1 and 3 years, then flatten or dip for 5-year and 10-year terms. Small finance banks and NBFCs often keep pushing rates higher at longer tenures, which is why the same ₹100,000 can earn meaningfully different interest at similarly named institutions.
At a flat 7.1% compounded quarterly, interest per ₹100,000 runs ₹7,291.28 at 12 months, ₹15,114.20 at 24, ₹23,507.50 at 36, and ₹42,174.67 at 60. Totals always grow with tenure, but the marginal year matters: the fifth year adds ₹18,667.17 while the first adds ₹7,291.28, so locking longer still pays when the rate holds.
Tenure choice is really a bet on the rate cycle. Locking five years near a rate peak secures income through a cutting cycle; locking long near a trough means watching better offers arrive while your money sits. A common middle path splits a sum across 1-, 3-, and 5-year tranches, which the laddering section below develops in full.
Tax, TDS, and Forms 15G and 15H
FD interest is taxed at your slab rate — a 30% marginal payer keeps barely two-thirds of a 7.1% deposit's return. Banks deduct 10% TDS under Section 194A once aggregate interest across deposits at that bank crosses the annual threshold: ₹50,000 for general depositors and ₹100,000 for senior citizens since April 2025. No TDS does not mean no tax; the liability simply shifts to your return.
Form 15G (under 60) or 15H (60 and above) tells the bank your total income falls below the taxable limit so it can skip TDS entirely. Submit a fresh form each financial year, at each branch where you hold deposits — an old form does not carry forward. Missing the submission means reclaiming deducted tax through your return, which delays the cash by months.
Cumulative deposits create a timing trap: TDS applies to interest as it accrues each year even though the cash arrives only at maturity, so a 3-year deposit can generate three years of tax bills with zero cash flow to cover them. Payout depositors face the mirror image — monthly interest counts as income in the year received, so retirees should map payouts against the ₹100,000 senior threshold before booking.
The Real Cost of Breaking a Deposit Early
Premature closure re-prices the deposit at the rate applicable to the tenure actually completed, minus a penalty — typically 0.5% to 1% at major banks. You do not keep the booked rate pro-rated; you receive the lower card rate for the shorter period, penalized further. Some banks refuse premature closure on special-rate deposits entirely, so read the booking terms before signing.
Concretely: a ₹100,000 3-year deposit booked at 7.1% and broken at 18 months, with the 18-month card rate at 6.75% and a 0.5% penalty, pays 6.25% for 1.5 years — ₹109,748.93. Staying the course would have accrued ₹111,133.93 by month 18 on the compounding path, so the break costs ₹1,385 plus all the forgone compounding through month 36.
The cheaper escape is a loan or overdraft against the FD — banks generally lend up to 90% of the deposit at 1 to 2 percentage points over the FD rate, and the deposit keeps compounding while the loan runs. For genuine emergencies, a funded emergency fund calculator target kept in liquid instruments prevents FD breaks from ever becoming necessary.
Fixed Deposits vs Inflation and Growth Options
At 7.1% nominal with 4% inflation — the midpoint of India's target band — the real return is 2.98%. The ₹123,507.50 maturity is worth about ₹109,797.72 in today's money, which is what an inflation calculator shows for any fixed nominal promise. FDs preserve capital in rupee terms but only creep ahead in purchasing-power terms.
That trade is acceptable for near-term goals and emergency reserves, weak for decade-long horizons. Index funds, equity SIPs, and pension schemes have out-earned FDs over rolling 10-year spans, with matching volatility. The Reserve Bank's inflation targeting keeps the 4% anchor visible — the CPI inflation calculator converts index readings into the exact hurdle your deposit rate must clear.
A practical split many savers use: fixed deposits for goals inside three years, growth assets beyond that, sized by a savings goal calculator rather than by instinct. The rule of 72 frames the wait — at 7.1%, money doubles in about 10.1 years inside an FD, versus roughly half that in equity index funds across long historical windows.
Laddering and Auto-Renewal Tactics
A ladder splits one sum into equal deposits maturing at staggered intervals — say 1, 2, and 3 years — then rolls each maturity into the longest rung. You get liquidity at every rung, a rolling average rate instead of one locked number, and protection against booking everything at a cyclical trough. The tenure table above supplies the per-rung interest you should expect at each step.
Auto-renewal re-books the deposit at maturity without your signature, at the prevailing card rate for the same tenure. Convenient, but card rates sit below special-scheme and negotiated rates often enough to matter on large sums — a 0.25% shortfall on ₹1,000,000 is more than ₹2,500 per year. Diarize maturities or enable bank alerts and re-shop every renewal.
Treat each maturity as a fresh allocation decision: compare the effective yield against current alternatives using the same framework this tool applies, and run growth options through an ROI calculator before defaulting back into another FD. Savers who re-shop at every rung consistently earn 25 to 50 basis points more than auto-renewal sleepers — worth ₹2,500 to ₹5,000 a year per ₹1,000,000 deployed.