Compound Interest Calculator
See the power of compounding at different frequencies. Understand how your principal grows and what it means after adjusting for inflation.
Principal
₹1 L
Interest Earned
₹46,933
Final Amount
₹1.47 L
Interest Breakdown
Compound Interest Calculator – See Your Money Grow
What is Compound Interest?
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, which is calculated only on the principal, compound interest creates a snowball effect — your money earns money on money, accelerating growth exponentially over time.
Albert Einstein reportedly called compound interest the "eighth wonder of the world." The longer you stay invested, the more dramatic the compounding effect becomes.
How Does the Compound Interest Calculator Work?
The calculator uses the standard compound interest formula: A = P × (1 + r/n)^(n×t), where P is the principal amount, r is the annual interest rate (decimal), n is the compounding frequency per year, and t is the time in years.
Compounding frequency matters significantly. Monthly compounding yields more than quarterly, which yields more than yearly — because interest starts earning interest sooner. For example, ₹1,00,000 at 10% for 10 years grows to ₹2,59,374 with yearly compounding but ₹2,70,704 with monthly compounding — a difference of over ₹11,000.
Why Compounding Frequency Matters
The more frequently interest is compounded, the higher your final amount. Indian banks typically compound quarterly for fixed deposits, while mutual funds compound daily. Understanding the frequency helps you compare products accurately.
Our calculator supports yearly, half-yearly, quarterly, and monthly compounding frequencies so you can model any financial product precisely.
Real Returns After Inflation
If your investment earns 10% but inflation is 5%, your real return is not simply 5%. The exact formula (Fisher equation) is: Real Return = (1 + Nominal Return) / (1 + Inflation) - 1. So your real return = (1.10 / 1.05) - 1 = 4.76%. This is what you actually gain in purchasing power.
This is critical for long-term goals like retirement — a ₹1 crore corpus in 20 years may only buy what ₹38 lakh buys today at 5% inflation. Always evaluate investments on real returns, not nominal headlines.
Frequently Asked Questions
Simple interest is calculated only on the principal: Interest = P × R × T. Compound interest is calculated on principal plus accumulated interest: A = P × (1 + r/n)^(n×t). Over long periods, compound interest produces significantly higher returns.
Higher compounding frequency yields slightly more returns. Monthly compounding > quarterly > half-yearly > yearly. However, the difference is modest for typical rates and durations. The stated interest rate matters more than the frequency.
The Rule of 72 is a quick estimate: divide 72 by your annual interest rate to find how many years it takes to double your money. At 8%, it takes roughly 9 years (72 ÷ 8 = 9). At 12%, about 6 years.
Nominal return is the headline rate (e.g., 10%). Real return is what you actually gain in purchasing power after inflation. The exact formula is: Real Return = (1 + Nominal Return) / (1 + Inflation) - 1. If your investment returns 10% and inflation is 5%, your real return is (1.10 / 1.05) - 1 = 4.76% — not the commonly quoted 5% approximation. Always consider real returns for long-term financial planning.
Over long periods, compounding becomes exponential. At 10% annual return, ₹1 lakh becomes ₹2.59 lakh in 10 years, ₹6.73 lakh in 20 years, and ₹17.45 lakh in 30 years. The last 10 years produce more growth than the first 20 combined — this is why starting early matters enormously.
Compound interest benefits most from time. In the short term (1–3 years), the compounding effect is modest. Over 10+ years, it becomes dramatic. For short-term needs, simple interest products may suffice. For wealth building, always choose compound interest instruments with long horizons.
Yes — on loans and credit cards, compounding works against you. Credit card interest compounds daily at 24–40% APR. A ₹50,000 unpaid balance at 36% can grow to ₹68,000 in just one year. This is why paying off high-interest debt should always be your first priority before investing.
Continuous compounding is the theoretical limit where interest compounds infinitely often. The formula is A = P × e^(rt), where e ≈ 2.718. In practice, daily compounding is very close to continuous compounding. The difference between daily and continuous compounding is negligible for typical rates.
Indian banks typically compound FD interest quarterly and savings account interest daily (credited quarterly). RBI mandates that savings interest be calculated on daily closing balances. For FDs, quarterly compounding is the industry standard, though some NBFCs offer monthly compounding.