What is compound interest formula?

Compound Interest = P × (1 + r/n)^(nt) − P, where P is principal, r is annual rate, n is compounding frequency per year, and t is time in years.

How does compounding frequency affect returns?

Higher compounding frequency means more frequent interest calculation. Monthly compounding gives higher returns than yearly compounding for same annual rate.

Which investments use compound interest in India?

Fixed deposits, PPF, EPF, mutual funds, NPS, and savings accounts all use compounding. Frequency varies by product type.

What is the difference between compound and simple interest?

Simple interest is calculated only on principal. Compound interest is calculated on principal plus accumulated interest, leading to exponential growth over time.

Compound Interest Calculator India 2026

Compound Interest Calculator India - Free Online Tool

Calculate compound interest instantly with yearly, quarterly, or monthly compounding. Get accurate results with detailed breakdowns, charts, and downloadable PDF reports - 100% free.

Assumptions and limitations

The formula is A = P(1 + r/n)^(nt), where n is the compounding frequency per year.
Interest rates are nominal annual rates entered as percentages.
The calculator does not model TDS, income tax, premature withdrawal penalty or floating-rate changes.
Results are rounded for display; banks may round according to their own product rules.

Illustrative projections only

SmartFintool provides mathematical calculations and educational information. It does not provide personalised investment advice. Mutual fund returns are not guaranteed and tax rules can change.

Page last updated: 24 August 2026
Methodology reviewed: 24 August 2026
Sources last checked: 24 August 2026

Read the calculation methodology

Compound Interest Calculator

Calculate compound interest with different frequencies

Principal Amt.

₹1,000₹1 Crore

Interest Rate (p.a)

1%30%

Time Period

Yrs

1 Year40 Years

Compounding Freq.

Summary

Principal

₹1,00,000

Interest

₹46,933

Total Amount

₹1,46,933

What is Compound Interest?

Compound Interest is the interest calculated on the initial principal amount as well as the accumulated interest from previous periods. Unlike simple interest, compound interest helps your money grow exponentially over time - which is why Albert Einstein reportedly called it the "eighth wonder of the world."

When you invest money with compound interest, your earnings start earning their own returns. This snowball effect makes compound interest one of the most powerful concepts in personal finance and wealth creation in India.

Compound Interest Formula

A = P (1 + r/n)^nt

Compound Interest (CI) = A - P

A = Final Amount (Principal + Interest)
P = Principal Amount (Initial investment)
r = Annual Interest Rate (in decimal, e.g., 10% = 0.10)
n = Number of times interest is compounded per year
t = Time period in years

Example Calculation

If you invest ₹1,00,000 at 10% annual interest rate for 10 years, compounded annually:

A = 1,00,000 × (1 + 0.10/1)^1×10 = ₹2,59,374

Compound Interest earned = ₹1,59,374

How to Use Compound Interest Calculator?

1Enter Principal Amount: The initial sum you want to invest (₹1,000 to ₹1 Crore).
2Set Interest Rate: Annual interest rate offered (1% to 30%).
3Choose Time Period: Investment duration in years (1 to 40 years).
4Select Compounding Frequency: Yearly, Quarterly, or Monthly compounding.
5View Results: Get instant breakdown of principal, interest earned, and total maturity amount with visual chart.

Benefits of Compound Interest

Exponential Growth

Money grows faster than simple interest due to interest-on-interest effect.

Wealth Creation

Long-term compounding can turn small investments into substantial wealth.

Beat Inflation

Higher compounding frequency helps your savings beat inflation effectively.

Retirement Planning

Perfect for long-term goals like retirement and child education.

Passive Income

Your money works for you, generating returns even when you sleep.

Reinvestment Power

Reinvested interest accelerates the growth of your investment portfolio.

Simple Interest vs Compound Interest

Parameter	Simple Interest	Compound Interest
Calculation	On principal only	On principal + accumulated interest
Formula	SI = (P × R × T) / 100	A = P(1 + r/n)^(nt)
Growth Rate	Linear (slower)	Exponential (faster)
Best For	Short-term loans	Long-term investments
Returns (₹1L @10% for 10yr)	₹2,00,000	₹2,59,374

Frequently Asked Questions (FAQs)

What is compound interest in simple terms?▼

Compound interest is "interest on interest." When you invest money, you earn interest not just on your original amount but also on the interest you have already earned. This makes your money grow much faster over time.

What is the formula for compound interest?▼

The compound interest formula is A = P(1 + r/n)^(nt), where A is the final amount, P is principal, r is annual interest rate (in decimal), n is number of times interest compounds per year, and t is time in years.

How is compound interest calculated monthly?▼

For monthly compounding, use n=12 in the formula. Example: ₹10,000 at 10% for 5 years monthly compounded = 10000 × (1 + 0.10/12)^(12×5) = ₹16,453.

Which compounding frequency is best?▼

Higher frequency = better returns. Monthly compounding gives more returns than quarterly, which gives more than yearly. However, the difference becomes smaller as frequency increases.

Is compound interest better than simple interest?▼

Yes, for investments compound interest is much better as it generates higher returns. However, for borrowers, simple interest is preferable as you pay less interest over time.

Does FD use compound interest in India?▼

Yes, most Fixed Deposits (FDs) in India use compound interest, typically compounded quarterly. Some banks offer monthly compounding for better returns.

What is the Rule of 72 in compound interest?▼

Rule of 72 is a quick formula to estimate how long it takes for money to double. Divide 72 by your annual interest rate. At 12% return, money doubles in approximately 6 years (72/12 = 6).

Can I download the compound interest calculation as PDF?▼

Yes, our calculator provides a free PDF download option. Click the "PDF" button in the results section to download your complete calculation report.

Is this compound interest calculator free?▼

Absolutely! SmartFintool's compound interest calculator is 100% free, requires no registration, and can be used unlimited times.

Is compound interest taxable in India?▼

Yes. Interest income from FD compounding is taxable as per income tax slab. Mutual fund gains have separate capital gains tax rules - LTCG above ₹1.25 lakh is taxed at 12.5% for equity funds.

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Disclaimer: The calculations provided by this compound interest calculator are for educational and illustrative purposes only. Actual returns may vary based on market conditions, tax implications, and other factors. Please consult a SEBI-registered financial advisor before making investment decisions.