The gap between the rate on the board and the money you keep is mostly tax, not arithmetic. Fixed deposit interest is added to your income and taxed at your slab rate, so the same deposit genuinely returns less to a higher earner than to a lower one. Compounding actually works in your favour; what closes the gap is the slab tax, the tax deducted each year before maturity, and inflation.
Key takeaways
- FD interest is taxed at your income slab rate rather than at a concessional investment rate, so the higher your income the less the deposit returns.
- Compounding lifts the effective yield above the quoted rate on a cumulative deposit, so it is not the reason you receive less.
- Interest is taxed as it accrues each year, not only in the year the deposit matures.
- Tax deducted at source is taken out as interest accrues, so that money leaves the deposit and stops compounding.
- The advertised rate is usually the best cell in a rate table rather than the rate that applies to your tenure and your age band.
Does compounding make you earn more or less?
More, and it is worth settling this first because compounding is often blamed for the shortfall.
Most Indian banks compound a cumulative fixed deposit at regular intervals within the year. Each period's interest is added to the balance and then earns interest itself. The result is that the amount you actually accrue over a year is slightly more than the quoted annual rate implies. That figure is called the effective yield, and Compounding is why it sits above the headline rate rather than below it.
The exception is a non-cumulative deposit, where interest is paid out to you at intervals instead of staying in. Nothing compounds inside the deposit, so you earn the simple quoted rate. If you spend those payouts, the quoted rate is exactly what you get. That is a fair trade when you want the income, but it is a different product from the cumulative version, and the two are often presented under the same headline number.
Where does most of the difference actually go?
Tax, at your slab rate. Interest on a fixed deposit is not treated as investment income with a concessional rate attached. It is added to your total income and taxed much like salary.
This has a consequence people rarely price in: the same deposit at the same bank on the same day returns different amounts to different people. Someone in the highest bracket keeps materially less of the interest than someone below the threshold for tax at all. A rate that looks competitive against another instrument before tax can lose that comparison decisively after it.
Interest is also taxed as it accrues rather than when the deposit matures. On a multi-year cumulative deposit, you owe tax on each year's interest in that year, even though no money has reached your hands yet. People who plan around a single tax bill at maturity are regularly caught out by this.
Use the planning tools on Artha Terminal to work a deposit through tax and inflation, so you compare what you keep rather than what you were quoted.
Why does tax deducted at source reduce what compounds?
TDS and tax are not the same thing. Tax deducted at source is a prepayment the bank collects on the government's behalf once your interest from that bank crosses a threshold for the year. The tax is what you finally owe at your slab. If too much was deducted you claim it back when you file; if too little was deducted you pay the balance.
Both the threshold and the deduction rate are set in tax law, are different for senior citizens, and are revised from time to time, so check the current position rather than relying on a figure quoted anywhere, including here. A higher rate typically applies where the bank does not have your PAN on record.
The part that quietly costs you is the timing rather than the amount. On a cumulative deposit the bank deducts as interest accrues, and that money leaves the deposit. It is no longer in the balance, so it no longer compounds. Over a long deposit, the compounding you actually receive is therefore a little lower than a clean compound-interest calculation suggests, before you have paid any of the remaining tax at your slab.
Can you stop the deduction if you owe no tax?
Yes, if your total tax liability for the year genuinely is nil. The mechanism is a self-declaration you file with your bank, after which the bank stops deducting at source from your interest.
The declaration has been reorganised more than once, including a consolidation of what were previously separate forms for different age groups into a single form. Because the form and its statutory reference change, the durable instruction is to ask your bank for the current declaration rather than to look for a form by name.
Two things about it do not change. The declaration only removes the deduction at source; it does not reduce tax you actually owe. And it is valid only where your liability really is nil, so filing it when tax is in fact payable is a false declaration rather than a saving.
What else quietly lowers the rate you were shown?
Two things, both common and both avoidable.
The first is that an advertised rate is usually the best cell in a table rather than the rate for your deposit. The largest number on display is often tied to one specific tenure, or is the senior-citizen rate, which typically carries an additional margin over the general rate. Read the rate against your own tenure and your own age band before assuming it applies to you.
The second is breaking the deposit early. When you withdraw before Maturity, most banks do not simply pay the contracted rate for the shorter period you held it. They re-fix the interest to the rate that applied to that shorter tenure, and then subtract a penalty on top. A deposit booked for a long tenure and broken early can therefore pay less than a deposit you had simply booked for the short tenure in the first place. Where you need money only briefly, a loan against the deposit is often cheaper than breaking it, because the deposit continues to earn while you borrow against it.
What is the number that actually matters?
The post-tax real return: what you keep after tax, measured against Inflation.
A deposit's quoted rate is a nominal figure. Subtract tax at your slab, then subtract the rate at which prices are rising, and what remains is the Real Return — the only number that tells you whether your purchasing power grew. For a taxpayer in a high bracket during a period of firm inflation, that remainder can be very close to nothing, while the same deposit can be genuinely worthwhile for someone taxed lightly or not at all.
None of this makes a fixed deposit a poor instrument. Certainty of principal and a known maturity value are real properties, and no market instrument offers them. The point is narrower: the headline rate is not the return, and an honest comparison against any alternative has to be made after tax, after inflation, and against How much of an FD is insured for the portion that is actually guaranteed.