Compound Interest Calculator
₹1 lakh at 8% grows to ₹2,20,804 in 10 years if interest is added every quarter. Change the frequency, add monthly or yearly top-ups, and compare every option side by side.
Same money, every compounding frequency
Year-by-year growth
Uses A = P(1 + r/n)nt. Part periods are compounded proportionally. Figures are before tax. Everything is calculated in your browser.
₹1 lakh at 8% for 10 years, five ways
The only thing that changes in this table is how often the interest is added to the balance.
| Compounding | Effective yearly rate | Final amount | Interest |
|---|---|---|---|
| Yearly | 8.000% | ₹2,15,892 | ₹1,15,892 |
| Half-yearly | 8.160% | ₹2,19,112 | ₹1,19,112 |
| Quarterly | 8.243% | ₹2,20,804 | ₹1,20,804 |
| Monthly | 8.300% | ₹2,21,964 | ₹1,21,964 |
| Daily | 8.328% | ₹2,22,535 | ₹1,22,535 |
Moving from yearly to quarterly adds ₹4,911 over the ten years. Going all the way to daily adds only another ₹1,731. The gains shrink because each extra compounding step adds interest on a smaller and smaller sliver of earlier interest.
Now change the rate instead. ₹1 lakh at 8.5% compounded just once a year ends at ₹2,26,098, which is ₹3,564 more than 8% compounded daily. When two deposits differ in both rate and frequency, compare their effective yearly rates. That single number folds both in, and the calculator shows it for whatever you enter.
Which frequency your scheme uses
It's written in the scheme rules or on the deposit receipt. As of the October–December 2026 quarter, the government's small savings table lists post office time deposits as compounding quarterly and PPF as compounding once a year. Many bank FDs compound quarterly too, but banks set their own terms, so check yours. Deposits that pay interest out to you every month or quarter don't compound at all; they earn simple interest.
The formula behind the table
For the quarterly row: 8% ÷ 4 is 2% a quarter, and ten years is 40 quarters, so A = 1,00,000 × 1.0240 ≈ ₹2,20,804. Simple interest at the same 8% would give ₹80,000 of interest, not ₹1,20,804.
Adding ₹2,000 every month
Start with ₹50,000 and add ₹2,000 at the end of every month for 10 years, at 8% compounded quarterly. The opening ₹50,000 grows to about ₹1,10,402. The 120 top-ups, ₹2,40,000 of your money, grow to about ₹3,64,817. The total is roughly ₹4,75,219, of which ₹1,85,219 is interest.
The balance at the end of year 5 is about ₹2,21,049, so the second five years add about ₹2,54,170 against ₹1,71,049 in the first five, even though you put in the same amount each year. Each top-up is grown for the time it has left: a deposit made with 9 years to go is multiplied by (1.02)36. For market-linked monthly investing, where returns aren't fixed, the SIP calculator uses the same idea.
Doubling time and the rule of 72
| Rate | 72 ÷ rate | Exact, yearly | Exact, quarterly |
|---|---|---|---|
| 6% | 12.0 years | 11.90 years | 11.64 years |
| 8% | 9.0 years | 9.01 years | 8.75 years |
| 10% | 7.2 years | 7.27 years | 7.02 years |
| 12% | 6.0 years | 6.12 years | 5.86 years |
The shortcut is close enough for a quick check in this range of rates. Time matters far more than frequency: ₹1 lakh at 10% compounded yearly is about ₹2.59 lakh after 10 years, ₹6.73 lakh after 20 and ₹17.45 lakh after 30. The same arithmetic runs against you on an unpaid credit card balance, and prices compound as well, which is why the inflation calculator is worth a look before you judge any return.
Frequently asked questions
Why doesn't this match my FD receipt exactly?
Banks may pay simple interest for a leftover part of a quarter, round at each step, or count days rather than years. This calculator compounds part periods smoothly, so for an odd tenure such as 2 years 5 months the bank's figure can differ by a few rupees. The FD calculator follows the bank method more closely.
Is the interest taxed?
Interest from most bank and post office deposits counts as income and is taxed at your slab rate. A few schemes, such as PPF, pay tax-free interest. The figures here are before tax, so a taxable deposit leaves you with less.
Can I use this for a loan?
For a loan where nothing is repaid and interest keeps being added, yes: the balance grows exactly like a deposit. For a loan you repay in instalments, use the EMI calculator, because each payment cuts the balance that interest is charged on.