How FD Interest Is Calculated in India (With Examples)

What a fixed deposit really is

A fixed deposit is a loan you give to a bank. You hand over a lump sum, the bank promises a fixed rate of interest, and you agree not to touch the money until the end of the term. In return for locking it away, you get a rate that is usually higher than a savings account and never changes during the term, even if market rates fall.

That last point is the real attraction. If you book a five-year FD at 7% and rates drop to 6% next year, your 7% stays. The flip side is also true. If rates rise, you are stuck with the old rate until you break the deposit or it matures.

In India, FDs are offered by banks, small finance banks and some non-bank companies. The deposit at a scheduled bank is covered by deposit insurance up to ₹5 lakh per depositor per bank, which includes both your principal and the interest. That is one reason many families treat FDs as the safe corner of their savings.

Simple interest vs compound interest

Simple interest is easy. You earn the same amount every year, calculated only on your original deposit. On ₹1,00,000 at 6.5% that is ₹6,500 a year, so ₹19,500 over three years.

Compound interest is different. At the end of each period the interest is added to your balance, and the next period earns interest on the bigger balance. Your money starts to grow on top of its own growth. That small difference is why the ₹1,00,000 grows to ₹1,21,341 and not ₹1,19,500.

Most bank FDs in India use compound interest. Some special schemes pay interest out to you every month or quarter instead, and those are called non-cumulative or payout deposits. In that case there is nothing to compound, because you take the interest out and spend it. The maturity amount is just your original deposit.

So the first thing to check on any FD offer is whether it is cumulative, where interest stays in the deposit and compounds, or non-cumulative, where interest is paid out. The same headline rate gives very different results.

The formula, in plain words

The maturity amount of a cumulative FD is worked out like this: A = P × (1 + r/n) ^ (n × t).

It looks scary, but each letter is simple. P is the money you deposit. r is the yearly interest rate written as a decimal, so 6.5% becomes 0.065. n is how many times a year the bank adds interest. t is the number of years. A is what you get at the end.

1. Take the yearly rate and divide it by how many times interest is added. For quarterly compounding that is 0.065 ÷ 4 = 0.01625.
2. Add 1 to get the growth factor for one quarter: 1.01625.
3. Count the total number of quarters. Three years is 12 quarters.
4. Multiply 1.01625 by itself 12 times. The result is about 1.2134.
5. Multiply your deposit by that number: ₹1,00,000 × 1.2134 = about ₹1,21,341.

You do not have to do this by hand. The free FD calculator does exactly these steps, and you can change the numbers as often as you like. It helps to understand the steps, though, because then you can sanity check any figure a bank or an agent shows you.

Why most Indian banks compound every quarter

Banks in India usually compound FD interest every quarter. That is the standard practice for most cumulative deposits, and it is why you will see the phrase quarterly compounding on rate cards. Some banks and some special deposits compound monthly, half-yearly or yearly, so always read the terms.

How much does the frequency matter? Here is the same ₹1,00,000 at 6.5% for three years under different compounding:

• Yearly compounding: about ₹1,20,795
• Half-yearly compounding: about ₹1,21,155
• Quarterly compounding: about ₹1,21,341
• Monthly compounding: about ₹1,21,467
• Simple interest, no compounding: ₹1,19,500

The jump from yearly to quarterly is about ₹546. Going from quarterly to monthly adds another ₹126. So frequency matters, but much less than the rate itself or the tenure. Do not choose between two banks only on compounding. A rate that is 0.25 percentage points higher will beat a better compounding schedule most of the time.

A related idea is the effective annual yield. A 6.5% rate compounded quarterly really earns about 6.66% over one year. When two banks quote the same headline rate but compound differently, comparing their effective yield tells you which one pays more.

How tenure changes the result

Time is the biggest lever you have. Compound growth is slow at first and then speeds up, because each year's interest is larger than the one before.

Take ₹1,00,000 at 6.5%, compounded quarterly. After one year it becomes about ₹1,06,660. After three years it is about ₹1,21,341. After ten years it is about ₹1,90,556. The last seven years added almost ₹70,000 of growth, while the first year added only ₹6,660.

That does not mean you should lock everything away for ten years. Rates change, your needs change, and breaking an FD early usually costs you. Banks normally cut the rate by around half to one percentage point for premature withdrawal, and some charge a small fee on top. A sensible approach is to match the tenure to the date you will need the money. If you need it for a school fee in two years, a two-year FD is the right tool, even if a five-year rate looks higher.

Tax and TDS: what you actually keep

The interest on an FD is taxable. It is added to your income and taxed at your slab rate, which means someone in the 30% bracket keeps only 70% of their interest. On the ₹21,341 earned in our example, that is about ₹14,939 after tax. In the 20% bracket you would keep about ₹17,073.

Banks also deduct TDS, tax deducted at source, when your total interest from a bank crosses a yearly limit. As per the rules that applied from April 2025, the limit was ₹50,000 for most people and ₹1,00,000 for senior citizens, with TDS of 10% when you give your PAN. Without a PAN the rate is higher. Rules like these are revised in the annual budget, so check the current figure on your bank's site or the income tax portal.

If your total income is below the taxable limit, you can submit Form 15G, or Form 15H if you are a senior citizen, so that the bank does not deduct TDS. This is a request not to deduct tax. It does not make the interest tax-free, so interest still needs to appear in your return when it applies.

Also remember that TDS is only an advance payment. Even if no TDS is cut because you stayed under the limit, the interest is still income and you must report it. Many people miss this, and it can lead to notices later.

Look past the headline: real returns after tax and inflation

A 6.5% FD sounds fine until you subtract two things: tax and inflation. If you are in the 30% bracket, your 6.5% turns into about 4.55% after tax. If prices rise 5% a year, you are barely staying even, and in some years you are going backwards.

To see this in rupees, imagine ₹1,00,000 today. If inflation runs at 5% for three years, that amount of buying power is worth about ₹86,400 in today's terms. Your FD grows, but the cost of things grows too. The honest question is not what your FD pays but what it pays after tax and after inflation.

This does not make FDs a bad choice. They are predictable, they are simple, and they are very good for money you cannot afford to lose or will need soon. It only means FDs are a poor tool for long-term growth on their own. For goals ten years away, many people also look at the PPF, which pays tax-free interest, or at market-linked options after reading about their risks.

FD or RD: which fits your situation?

An FD needs a lump sum. If you do not have one, a recurring deposit, or RD, lets you save a fixed amount every month and uses the same compounding rules. Saving ₹5,000 a month for five years at 6.5% grows to about ₹3,54,954. You pay in ₹3,00,000, so the interest is about ₹54,954.

Notice that RD interest looks lower compared to the total you put in. That is because each instalment only earns interest from the day you pay it. The first instalment works for five years, the last for one month. You can try your own figures in the RD calculator.

A neat trick many savers use is the FD ladder. Instead of putting everything in one deposit, you split the money into several FDs of different lengths, for example one, two, three, four and five years. Each year one FD matures. You can use that money or renew it at the current rate. The ladder gives you regular access to cash and protects you from locking everything in at a bad time.

A simple way to compare two FD offers

When two offers look alike, work through a short checklist. It takes five minutes and can save you real money.

1. Is the deposit cumulative or does it pay out interest? Compare like with like.
2. What is the compounding frequency? Quarterly is common. Compare effective yield if the schedules differ.
3. What is the exact tenure that gets the quoted rate? Some banks give the best rate only for odd tenures like 390 days.
4. What is the penalty for early withdrawal, and is there a minimum lock-in?
5. Are you eligible for a senior citizen rate, and does the bank restrict it to certain tenures?
6. How safe is the institution? Stick to well-known banks, and keep each deposit within the insured limit if the amount is large.

Then put each offer into the FD calculator and compare the maturity amount. Seeing two rupee figures side by side is far clearer than comparing 6.5% with 6.6%.

Five common FD mistakes

After years of seeing how people use FDs, a few mistakes come up again and again.

• Breaking an FD early for a small need, when a short loan against the FD would cost less than the lost interest.
• Ignoring tax. The interest is taxable, and the TDS cut is not the final word.
• Putting everything into one long FD and then needing cash in year two.
• Chasing the highest rate at a weak institution. A tiny extra rate is not worth a big risk.
• Forgetting to renew. Many banks auto-renew at the then-current rate, which may be lower. Set a reminder a week before maturity.

None of these is hard to avoid. A little planning before you sign is usually enough.

Questions people ask

Sources and further reading

• Reserve Bank of India – Deposit Insurance (DICGC)
• Income Tax Department of India – TDS and tax rules
• Reserve Bank of India – Financial education for savers