Compounding does the heavy lifting late
In year 1 the interest on ₹1,00,000 at 8% is ₹8,243. By year 10 the interest in a single year is ₹16,815 — more than double — because every earlier year's interest is now earning interest too.
Free compound interest calculator
Compound Interest Calculator
Enter your lump sum, an optional monthly deposit, the rate and the tenure — and get the maturity value, the interest earned, the effective annual rate and a year-by-year growth table.
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₹2,20,804 maturity value
On ₹1,00,000 at 8% a year, compounded quarterly for 10 years
₹1,20,804 interest earned
₹40,804 more than simple interest would pay at the same rate
8.24% effective annual rate
8% nominal, compounded quarterly, really earns 8.24% a year
Growth before tax at a steady rate — not investment advice. This tool shows growth before tax at a steady rate you enter — it is not investment advice. Real returns vary, and interest on most savings in India is taxable. Check the rules table below before you rely on it.
Calculate compound interest
₹1,00,000 at 8% for 10 years, quarterlyExample figures are filled in. Replace them with your own numbers.
YOUR ANSWER
WORKING SHOWN BELOW
Your answer
₹2,20,804
MATURITY VALUE
₹1,20,804
INTEREST EARNED
₹1,00,000
TOTAL INVESTED
Your answer at a glance
₹1,00,000 · 8% · 10 years · quarterly → maturity ₹2,20,804 (interest ₹1,20,804).
₹1,00,000 at 8% a year, compounded quarterly for 10 years, grows to ₹2,20,804 — ₹1,20,804 of interest on ₹1,00,000 invested.
A = ₹1,00,000 × (1 + 8% ÷ 4)^(4 × 10) = ₹2,20,804.
Quarterly compounding · effective annual rate 8.24% · money doubles in about 8.8 years.
The figure is growth before tax at the steady rate you enter. Real returns vary — mutual fund SIP returns are market-linked and not guaranteed — and interest on most savings in India is taxable.
Recent checks · this session
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Year by year
How the balance grows
The balance grows year by year — the interest column overtakes the deposits column as compounding takes over.
| Year | Opening balance | Deposits | Interest | Closing balance |
|---|---|---|---|---|
| Year 1 | ₹1,00,000 | ₹0 | ₹8,243 | ₹1,08,243 |
| Year 2 | ₹1,08,243 | ₹0 | ₹8,923 | ₹1,17,166 |
| Year 3 | ₹1,17,166 | ₹0 | ₹9,658 | ₹1,26,824 |
| Year 4 | ₹1,26,824 | ₹0 | ₹10,455 | ₹1,37,279 |
| Year 5 | ₹1,37,279 | ₹0 | ₹11,316 | ₹1,48,595 |
| Year 6 | ₹1,48,595 | ₹0 | ₹12,249 | ₹1,60,844 |
| Year 7 | ₹1,60,844 | ₹0 | ₹13,258 | ₹1,74,102 |
| Year 8 | ₹1,74,102 | ₹0 | ₹14,352 | ₹1,88,454 |
| Year 9 | ₹1,88,454 | ₹0 | ₹15,535 | ₹2,03,989 |
| Year 10 | ₹2,03,989 | ₹0 | ₹16,815 | ₹2,20,804 |
Understand the result
What does a compound interest calculator do?
Compound interest is interest earned on interest: the interest your money earns is added to the balance, and the next round of interest is calculated on the bigger balance. Over ten years at 8%, ₹1,00,000 grows to ₹2,20,804 compounded quarterly — ₹40,804 more than simple interest would pay. This calculator works out the maturity value for a lump sum, with an optional monthly deposit, at any compounding frequency, and shows the year-by-year growth so you can see the compounding take over.
More often is more
The same ₹1,00,000 at 8% for 10 years gives ₹2,15,892 compounded yearly and ₹2,20,804 compounded quarterly — ₹4,912 more, just for joining the balance four times a year instead of once.
Small deposits, big finish
₹10,000 a month at 12% for 10 years turns ₹12,00,000 of deposits into ₹23,00,387. The deposits do the early work; in the later years the interest each year is bigger than a whole year's deposits.
How it works
From your lump sum and rate to a maturity value
Enter your lump sum first — the other figures are already filled in with the usual example — then read the maturity value and the growth table.
Enter your lump sum
The amount you start with — from ₹0 to ₹1,00,00,000. Enter 0 if you are starting from scratch with monthly deposits.
Add a monthly deposit if you have one
From ₹0 to ₹10,00,000 a month, added at the end of each month. Leave it at 0 for a plain lump-sum calculation.
Set the rate, tenure and compounding frequency
Rate from 0% to 20% a year; tenure up to 30 years, in years and extra months; compounding yearly, half-yearly, quarterly, monthly or daily — quarterly is the Indian FD default.
Read the maturity value and the growth table
The answer appears as you type — maturity value, total invested, interest earned, the effective annual rate and a year-by-year table of how the balance builds.
The calculation, explained
How compound interest is calculated
Maturity value A = P × (1 + r/n)^(n×t), where P is the lump sum, r the yearly rate as a decimal, n the number of times a year interest compounds and t the tenure in years. Each monthly deposit is added at the end of its month and compounds from then on, so the maturity value is the compounded lump sum plus the compounded value of every deposit. The effective annual rate is (1 + r/n)^n − 1.
1. ₹1,00,000 at 8%, quarterly, 10 years
2,20,804 maturity · 1,20,804 interest
₹1,00,000 × (1 + 0.08 ÷ 4)^(4 × 10) = ₹2,20,804. Simple interest at the same rate would pay only ₹80,000 — compounding adds ₹40,804.
2. Same money, yearly compounding
2,15,892 maturity · 1,15,892 interest
₹1,00,000 × 1.08^10 = ₹2,15,892. The frequency alone costs ₹4,912 over ten years — the interest joins the balance once a year instead of four times.
3. ₹10,000 a month at 12%, monthly, 10 years
23,00,387 maturity · 11,00,387 interest
₹12,00,000 deposited over 120 months grows to ₹23,00,387. Start-of-month deposits would give 23,23,391 — ₹23,004 more — because every deposit earns one extra month.
The end-of-month convention: why two calculators can disagree
On ₹10,000 a month at 12% for 10 years with monthly compounding, deposits at the end of each month give ₹23,00,387. The same deposits at the start of each month give ₹23,23,391 — ₹23,004 more — because every deposit earns one extra month of growth. Both answers are right under their own convention, so check which one a calculator uses before comparing figures. This calculator adds each monthly deposit at the end of its month, the convention the ranking compound-interest calculators use: credocalc's published example — ₹1,00,000 plus ₹10,000 a month at 7% for 15 years — reproduces exactly at ₹34,41,686.
Worked examples
Five cases, five maturity values
One example for each everyday case, including one with monthly deposits only and one where the frequency is the whole story. Select any example to load it into the calculator and check the working for yourself.
₹1,00,000 at 8% for 10 years: ₹2,20,804
₹1,00,000 at 8% a year, compounded quarterly for 10 years. The maturity value is ₹2,20,804 — ₹1,20,804 of interest on ₹1,00,000 invested. Simple interest at the same rate would pay only ₹80,000.
₹1,00,000 → maturity ₹2,20,804
₹10,000 a month at 12% for 10 years: ₹23,00,387
No lump sum — ₹10,000 a month for 10 years at 12%, compounded monthly. You put in ₹12,00,000 and the maturity value is ₹23,00,387, so the interest is ₹11,00,387 — nearly as much as you deposited.
₹0 + ₹10,000 a month → maturity ₹23,00,387
Same ₹1,00,000 at 8%, yearly compounding: ₹2,15,892
The same ₹1,00,000 at the same 8% for the same 10 years, but compounded once a year instead of quarterly. The maturity value is ₹2,15,892 — ₹4,912 less — because the interest joins the balance only once a year.
₹1,00,000 → maturity ₹2,15,892
₹1,00,000 plus ₹10,000 a month at 7% for 15 years: ₹34,41,686
₹1,00,000 to start and ₹10,000 a month for 15 years at 7%, compounded quarterly. You put in ₹19,00,000 and the maturity value is ₹34,41,686 — ₹15,41,686 of interest, and the interest overtakes the deposits in year 10.
₹1,00,000 + ₹10,000 a month → maturity ₹34,41,686
₹5,000 a month at 6% for 1 year: ₹61,678
₹5,000 a month for one year at 6%, compounded monthly. You put in ₹60,000 and get back ₹61,678 — ₹1,678 of interest. In the first year the deposits do almost all the work; compounding takes over later.
₹0 + ₹5,000 a month → maturity ₹61,678
Compound interest rules at a glance
Compound interest rules at a glance
The formula, the compounding frequencies, the effective annual rate, the monthly-deposit convention, the rule of 72, the simple-interest comparison, the tax position and inflation. Every figure here is arithmetic from the formula — never a quoted rate or a forecast.
| Figure | Rule | What it means |
|---|---|---|
| A = P × (1 + r/n)^(n×t) | The formula | Maturity value A from principal P, annual rate r as a decimal, n compounding periods a year and t years. Compound interest is A minus what you put in. |
| Quarterly — 4 times a year | The Indian FD default | Most Indian bank fixed deposits compound quarterly, so the calculator starts on Quarterly. RDs compound quarterly too; PPF interest is credited yearly. |
| Effective annual rate | What the rate really earns | At 10% a year the effective rate is 10.47% monthly, 10.38% quarterly, 10.25% half-yearly and exactly 10.00% yearly — the same nominal rate earns more the more often it compounds. |
| Monthly additions | End of each month | Each monthly deposit is added at the end of its month and compounds from then on. A deposit made at the start of the month would earn one extra month — that is why two calculators can disagree. |
| Rule of 72 | Years to double your money | Divide 72 by the yearly rate: at 8% money doubles in about 9 years. Quarterly compounding at 8% doubles it in about 8.8 years; yearly compounding takes about 9.0 years. |
| Simple vs compound | The comparison | At 8% for 10 years, ₹1,00,000 earns ₹80,000 of simple interest but ₹1,20,804 compounded quarterly — ₹40,804 more, because interest earns interest. |
| Tax on interest | Before tax, not after | Interest on most savings in India is added to your income and taxed at your slab rate. This calculator shows growth before tax — use the FD calculator for the TDS flag and the income-tax calculator for the slab. |
| Inflation | What the money will buy | A 4% inflation rate halves purchasing power in about 18 years. This calculator shows the nominal maturity value; it does not adjust for inflation. |
The formula is fixed — the rate, the frequency and the tenure decide everything. The only judgement call is the deposit timing, and this page states it plainly: end of each month.
Common mistakes
Four ways to get compound interest wrong
The formula is short, but four readings trip people up. Each one can cost thousands.
Mixing up monthly and yearly rates
The calculator always takes a yearly rate. Entering 1% a month as 1% a year understates the growth twelvefold; entering 12% a year as a monthly rate overstates it wildly. If your bank quotes a monthly rate, multiply it by 12 first.
Comparing calculators on different conventions
On ₹10,000 a month at 12% for 10 years, start-of-month deposits give ₹23,23,391 and end-of-month deposits give ₹23,00,387 — ₹23,004 apart, both right under their own convention. Check the timing before you call one calculator wrong.
Forgetting the frequency
10% a year is not one rate: it earns 10.47% effective monthly, 10.38% quarterly, 10.25% half-yearly and exactly 10.00% yearly. Two deposits at the same nominal rate can mature ₹4,912 apart on ₹1,00,000 over ten years — compare effective rates, not nominal ones.
Treating the maturity value as what you keep
The maturity value is growth before tax at a steady rate. Interest on most savings in India is taxed at your slab rate, and 4% inflation halves purchasing power in about 18 years. The figure is a plan, not a promise — and for mutual funds the rate itself is never guaranteed.
Your questions, answered
Compound interest calculator FAQs
What is compound interest?
Compound interest is interest calculated on the initial principal as well as on the interest that has already accumulated. ₹1,00,000 at 8% a year, compounded quarterly for 10 years, grows to ₹2,20,804 — ₹1,20,804 of interest. Simple interest at the same rate would pay only ₹80,000, so compounding adds ₹40,804.
What is the compound interest formula?
A = P × (1 + r/n)^(n×t). P is the lump sum, r the yearly rate as a decimal, n how many times a year interest compounds and t the tenure in years. A is the maturity value, and the compound interest is A minus what you put in. For ₹1,00,000 at 8% compounded quarterly for 10 years: ₹1,00,000 × (1 + 0.08 ÷ 4)^(4 × 10) = ₹2,20,804.
How often do Indian bank FDs compound interest?
Most Indian bank fixed deposits compound quarterly — that is why this calculator starts on Quarterly. Recurring deposits compound quarterly too, and PPF interest is credited yearly. If your deposit compounds differently, pick its frequency from the list; the same rate earns more the more often it compounds.
How do monthly additions work in this calculator?
Each monthly deposit is added at the end of its month and then compounds at the same rate and frequency as the rest of the balance. ₹10,000 a month at 12% compounded monthly for 10 years gives ₹23,00,387 on ₹12,00,000 deposited. Deposits at the start of the month would give ₹23,23,391 — ₹23,004 more — so the timing matters.
Why do two compound interest calculators disagree?
Usually the deposit timing: end-of-month deposits earn one month less than start-of-month deposits on every instalment. Rounding is the other cause — this calculator compounds on the exact balance and rounds only the final maturity value, while a calculator that rounds every period can drift by a few rupees. Check the frequency too: quarterly and monthly compounding at the same rate give different answers.
How long does money take to double?
Divide 72 by the yearly rate — the rule of 72. At 8% money doubles in about 9 years. Exactly: quarterly compounding at 8% doubles it in about 8.8 years, yearly compounding in about 9.0 years. At 6% it takes about 12 years; at 12%, about 6 years.
Is the interest taxable in India?
Yes. Interest on most savings, such as FDs, is added to your income and taxed at your slab rate, and banks may deduct TDS once yearly interest crosses a threshold. This calculator shows growth before tax — it does not estimate what you keep. Use the FD calculator for the TDS flag and the income-tax calculator for the slab.
Does this calculator adjust for inflation?
No — it shows the nominal maturity value, what the balance will be in rupees. At 4% inflation, what ₹1,00,000 buys today costs about ₹1,48,000 in ten years, so the real growth is smaller than the nominal figure. Treat the result as growth before tax at a steady rate, not as a forecast.
Does this calculator send my numbers anywhere?
No. Every calculation runs entirely on this page — nothing is sent to a server, nothing is stored, and reloading the page clears your recent checks.
About the method
This page uses the standard compound interest formula: maturity value A = P × (1 + r/n)^(n×t), where P is the lump sum, r the yearly rate as a decimal, n the number of times a year interest compounds and t the tenure in years. Each monthly deposit is added at the end of its month and compounds from then on at the same rate and frequency, so the maturity value is the compounded lump sum plus the compounded value of every deposit. The effective annual rate is (1 + r/n)^n − 1. The calculator compounds on the exact balance and rounds only the final maturity value to the nearest rupee; the year-by-year table rounds each row to the nearest rupee, so each row's interest is its closing balance minus its opening balance minus that year's deposits. Part years use the same formula with a fractional power. The rate is user-entered and treated as a steady assumption — never as a live quote or a forecast.
Figures checked 12 November 2026: the formula and the worked examples against the ranking compound interest calculators — the blogbanking.com example, ₹1,00,000 at 8% compounded quarterly for 10 years, gives ₹2,20,804 (interest ₹1,20,804) on blogbanking.com; the srutved.com example, ₹1,00,000 at 8% compounded yearly for 10 years, gives ₹2,15,892 on srutved.com; the credocalc.com example, ₹1,00,000 plus ₹10,000 a month at 7% compounded quarterly for 15 years, gives ₹34,41,686 (₹19,00,000 invested + ₹15,41,686 interest) on credocalc.com; the effective annual rates at 10% a year — 10.47% monthly, 10.38% quarterly, 10.25% half-yearly, 10.00% yearly — match the BusinessToday calculator on businesstoday.in. For a bank deposit with TDS and tax on interest, use the FD calculator; for a recurring deposit, the RD calculator; for a systematic monthly investment, the SIP calculator — all three use the same compounding maths with their own product rules. One honest limit: this calculator takes a single steady rate, so it cannot model returns that change year to year — for market-linked investments, try a lower rate too.
Check another plan before you start
Try different numbers — or run the same check with the related tools for your other plans.
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