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Compound Interest Calculator
See how compounding grows a deposit at different rates and frequencies. Adjust any input below and your results update instantly.
Understanding compound interest
The concept, the motivation, and what to watch out for.
What is compound interest?
Compound interest is interest calculated not just on your original deposit, but also on the interest that deposit has already earned — so your money grows on an increasingly larger base each period.
How often that interest is added back — the compounding frequency — changes your actual return even at the same stated annual rate: more frequent compounding means interest starts earning its own interest sooner.
Frequency matters more than people expect
Two deposits at the same annual rate can mature to different amounts purely because one compounds quarterly and the other compounds annually.
It's the same math behind FDs, RDs, and bonds
Whether it's a bank fixed deposit, a recurring deposit, or a bond, the same compounding formula applies — only the rate and frequency differ.
How this calculator helps
Choose your deposit, rate, term, and compounding frequency — your maturity value updates instantly, with the full formula and year-by-year growth shown alongside it.
Calculate your compound interest
Fill in the starred fields on the left — your results update instantly on the right.
Your details
e.g. quarterly for most Indian bank fixed deposits
≈ ₹1.00 L
e.g. ₹1,00,000 in a fixed deposit
e.g. 7% for a bank fixed deposit
e.g. 5 years
How these compare
vs. typical India long-term ranges
Annual interest rate: 7%
Typical FD/RD rate: 5–8%
These are example numbers. Edit any input on the left to see your own.
Your deposit grows to
₹1.41 L
compounded quarterly
Deposit amount
₹1.00 L
Interest earned
₹41,478
Deposit value vs. principal
Deposit valuePrincipal
Year-by-year breakdown
"% is interest" shows how much of that year’s value is compounding gains rather than your original deposit.
YearDeposit valuePrincipalStatus
1₹1.07 L₹1.00 L
1.07x deposit
7% is interest
2₹1.15 L₹1.00 L
1.15x deposit
13% is interest
3₹1.23 L₹1.00 L
1.23x deposit
19% is interest
4₹1.32 L₹1.00 L
1.32x deposit
24% is interest
5₹1.41 L₹1.00 L
1.41x deposit
29% is interest
Compare scenarios
See how small changes move your maturity value.
Your plan
7% · 5y
₹1.41 L
Maturity value
Baseline
Rate +2%
9% · 5y
₹1.56 L
Maturity value
+₹14,573
+5 years
7% · 10y
₹2.00 L
Maturity value
+₹58,682
Worked example, using your numbers
A step-by-step walkthrough of how your deposit becomes your maturity value.
Step 1 · Per-period rate
Your 7% annual rate, compounded quarterly, converts to a per-period rate of
1.750%
Step 2 · Compounding over time
Compounding 20 times over 5 years grows ₹1.00 L to
₹1.41 L
Step 3 · Interest earned
Of that final value, pure interest accounts for
₹41,478
✓
Your ₹1.00 L deposit grows to ₹1.41 L — compounded quarterly over 5 years.
Personalised insights
What your numbers reveal, and what changing them would do.
Your ₹1.00 L deposit grows to ₹1.41 L
Compounded quarterly at 7% for 5 years, that's ₹41,478 in interest.
Compounding quarterly instead of annually adds ₹1,223
At the same 7% rate, annual compounding alone would only reach ₹1.40 L.
29% of your maturity value is pure interest
₹1.00 L deposited grows to ₹1.41 L — the remaining ₹41,478 is interest earned.
Staying invested 5 more years adds ₹58,682
At 7% for 10 years instead of 5, your deposit would grow to ₹2.00 L. A +2% rate instead adds ₹14,573.
How this is calculated
Every step of the math behind your result, shown in the open.
Converting to a per-period rate
r = annual interest rate, n = compounding frequency per year
Your annual rate (r) is divided by how many times a year it compounds (n), since interest is credited — and starts earning its own interest — every period, not just once a year.
Example: 7% ÷ 4 → 1.750% per period
Compounding over time
P = principal, t = years, A = maturity value
Your deposit (P) grows by the per-period rate, compounded once for every period across the full term — n times a year, for t years.
Example: ₹1.00 L compounded quarterly for 5 years → ₹1.41 L
Estimating interest earned
A = maturity value, P = principal
Subtracting your original deposit from the maturity value shows how much of your final balance is interest rather than your own money.
Example: ₹1.41 L − ₹1.00 L → ₹41,478 gained
Assumptions
- The interest rate stays fixed for the entire term — it isn't reset periodically like a floating-rate product.
- No withdrawals or additional deposits are made during the term.
- Figures are indicative and pre-tax — not financial advice.
Did you know?
A few facts behind compound interest.
72
The Rule of 72
Divide 72 by your annual rate to estimate doubling time — at 7%, a deposit roughly doubles every 10 years, regardless of compounding frequency.
∞
There's a mathematical limit to compounding
As compounding frequency increases toward continuous (infinite times a year), the maturity value approaches — but never exceeds — a fixed ceiling defined by e^(rt).
Q
Quarterly is the Indian banking default
Most Indian bank fixed deposits compound interest quarterly by default, which is why it's the most commonly quoted FD maturity figure.
1700s
Compound interest is centuries old
The mathematics of compound interest was already being studied and tabulated by mathematicians well before modern banking existed.
Frequently asked questions
Straight answers to the questions we hear most about compound interest.
What is compound interest?
Compound interest is interest calculated on both your original deposit and any interest it has already earned, so your balance grows on an increasingly larger base over time — unlike simple interest, which is always calculated on the original amount only.
Does compounding frequency really make a difference?
Yes. At the same annual rate, a deposit that compounds monthly or daily will mature to a slightly larger amount than one that compounds only annually, because interest starts earning its own interest sooner.
How is this different from a fixed deposit calculator?
This calculator applies the same general compound interest formula that underlies FDs, RDs, and bonds — a dedicated fixed deposit calculator may add specifics like premature withdrawal penalties or bank-specific rate slabs.
What compounding frequency do Indian banks typically use?
Most Indian bank fixed deposits compound quarterly, though this varies by bank and product — always check your specific FD's terms rather than assuming.
Does this account for tax on interest earned?
No, figures here are indicative and pre-tax. Interest income from deposits is fully taxable at your income tax slab rate in India.
Is this financial advice?
No. This tool provides indicative estimates based on your assumptions. Consult a certified financial advisor before making investment decisions.
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Learn more
Articles to go deeper on the ideas behind this calculator.
Fundamentals
Simple interest vs compound interest
Why the same rate can produce very different results depending on how it's calculated.
5 min read
Fundamentals
How compounding frequency affects your returns
The real difference between annual, quarterly, monthly, and daily compounding.
5 min read
Strategy
The Rule of 72, explained
A quick mental shortcut for estimating how long money takes to double.
4 min read