FD Calculator

How a Fixed Deposit Calculator Works

A fixed deposit (FD) is one of the simplest and safest ways to grow money: you lock a lump sum with a bank for a fixed period at a fixed interest rate, and in return the bank pays you a guaranteed return. A fixed deposit calculator turns the terms of that deposit — how much you put in, the rate, the tenure, and how often interest compounds — into a single maturity figure, so you know exactly what you will receive at the end.

For a cumulative FD, where interest is reinvested rather than paid out, the maturity value follows the compound-interest formula:

A = P × (1 + r/n)^n×t

Here P is your principal, r is the annual interest rate written as a decimal (7% becomes 0.07), n is the number of times interest is compounded each year, and t is the tenure in years. The interest you earn is simply the maturity amount minus what you deposited, A − P. The breakdown table above shows this one period at a time, so you can watch the balance grow as each round of interest is added.

A worked example

Deposit ₹1,00,000 at 7% for five years, compounded quarterly. There are four compounding periods a year, so over five years interest is added twenty times, each time at 7% ÷ 4 = 1.75% of the running balance. The deposit matures at about ₹1,41,478, meaning you earn roughly ₹41,478 in interest without ever touching the account. Because each quarter's interest joins the principal and then earns interest itself, the total is a little more than you would get from simple interest on the original ₹1,00,000.

Why compounding frequency matters

Two FDs can advertise the same headline rate yet pay slightly different amounts, and the reason is compounding frequency. The more often interest is added to your balance, the sooner it starts earning interest of its own. At the same 7% nominal rate, monthly compounding beats quarterly, which beats half-yearly, which beats annual. The gap is small on short tenures but grows over time. The single number that captures this is the effective annual yield: 7% compounded quarterly is equivalent to about 7.19% compounded once a year. When you compare deposits across banks, comparing effective yields is fairer than comparing headline rates.

Cumulative versus non-cumulative FDs

This calculator models a cumulative FD, where interest is reinvested and paid together with the principal at maturity — that is what makes it compound. A non-cumulative FD instead pays the interest out to you at regular intervals (monthly, quarterly, or annually), which suits retirees and anyone who wants a steady income stream. Because the interest leaves the account, a non-cumulative FD does not compound, so its total payout over the same tenure is a little lower than the cumulative version.

Tax on FD interest

Fixed deposit interest is fully taxable. It is added to your income and taxed at your slab rate, and banks deduct TDS (tax deducted at source) once your interest for the year crosses the applicable threshold. The maturity figure shown here is gross — it does not subtract TDS or income tax, so the amount that actually reaches your account will be lower depending on your tax bracket. If you fall in a higher slab, factor that in before comparing an FD against tax-advantaged options.

Premature withdrawal and laddering

Locking money away is the trade-off for a guaranteed rate. If you break an FD early, the bank typically pays interest only for the period the deposit actually ran, at the rate that applied to that shorter tenure, minus a small penalty of around 0.5% to 1%. One way to keep flexibility without giving up returns is laddering: split your money across several FDs with staggered maturities, so a portion becomes available at regular intervals while the rest keeps earning. This calculator assumes the deposit is held to its full tenure, which gives you the best-case maturity value to plan around.

How safe is a fixed deposit?

Fixed deposits are among the lowest-risk places to keep money, which is why they anchor so many conservative portfolios. In India, bank deposits are insured by the DICGC up to ₹5,00,000 per depositor per bank, covering both principal and interest, so even in the rare event of a bank failure your money up to that limit is protected. The trade-off for this safety is a modest return: over long horizons an FD will usually trail equity or a diversified SIP, and if its rate is close to inflation, your real (inflation-adjusted) return can be small. FDs are best used for capital you cannot afford to put at risk or money you will need on a known date, rather than for long-term wealth building.

Using your results

Start with the amount you can comfortably lock away and the date you expect to need it, then adjust the tenure and compounding frequency to see how the maturity value changes. Use the effective yield to compare offers on an equal footing, and download the period-by-period breakdown as a CSV if you want to keep a record or compare a few scenarios side by side. Remember that the real, post-tax return is what matters for your plan — treat the gross figure here as the starting point.