Multi-Frequency Compounding • Optional Regular Contributions

Compound Interest Calculator

Harness the eighth wonder of the world. Calculate exact compound interest, effective annual rate (AER), and optional recurring deposits across daily, monthly, quarterly, semi-annual, and annual cycles.

Effective Annual Rate (AER)•5 Compounding Frequencies•Monthly Deposit Option•100% Free & Private

Compounding Variables

0ms Local Engine

Initial Principal (₹)

₹

₹10,000₹1.00 L₹20 Lakhs

Annual Interest Rate (% p.a.)

Tenure (Years)

Yrs

Compounding Frequency

Final Maturity Amount

₹1,52,279

Effective EAR8.775% p.a.

Total Principal:

₹1,00,000

Total Interest Earned:

₹52,279

Principal (66%)Compound Interest (34%)

Calculated with 0ms client engine. Zero financial data stored or transmitted.

The Mathematical Foundation of Compounding Interest

Explore the mechanics of exponential curves, compounding frequency effects, and regular contribution modeling.

1. Simple Interest vs. Compound Interest

In simple interest, your returns grow linearly (a straight line) because only the original principal generates interest:

Simple Interest = P × r × t

Compound Interest: A = P × (1 + r/n)^(n × t)

Over a 20-year span at 10% annual interest on ₹1,00,000, simple interest generates ₹2,00,000 in interest (total ₹3 Lakhs), whereas annual compounding generates ₹5,72,750 in interest (total ₹6.73 Lakhs) — more than double the simple interest outcome.

2. Impact of Compounding Frequencies

For a nominal rate of 10% per annum on ₹1,00,000 over 5 years, here is how compounding frequency alters the effective return:

Compounding Cycle	Periods / Year (n)	Effective Annual Rate (EAR)	5-Year Maturity
Annually	1	10.00%	₹1,61,051
Semi-Annually	2	10.25%	₹1,62,889
Quarterly (RBI Bank FD Norm)	4	10.38%	₹1,63,862
Monthly (Recurring Deposit Norm)	12	10.47%	₹1,64,531
Daily	365	10.51%	₹1,64,861

3. The Three Levers of Wealth Accumulation

Time Horizon (n)

The exponential exponent. Starting 5 years earlier often creates more wealth than doubling your contribution later.

Rate of Return (r)

Diversifying into equities or mutual funds for 12% CAGR versus keeping cash at 3.5% in a savings bank account.

Regular Deposits

Adding monthly savings into the compounding pot compounds both old and new contributions concurrently.

Frequently Asked Questions on Compound Interest

Master the math, frequencies, and real-world effects of compounding interest.

What is compound interest and how does it work?

Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. In simple terms, it is "interest on interest", creating exponential growth as your investment horizon expands.

What is the formula for compound interest?

The standard formula is: A = P × (1 + r/n)^(n × t), where A is the final maturity amount, P is the principal, r is the annual nominal interest rate (decimal), n is the number of compounding periods per year (e.g. 4 for quarterly, 12 for monthly), and t is the time in years.

What is the Effective Annual Rate (EAR / AER)?

The Effective Annual Rate reflects the true annual return when interest is compounded more frequently than once a year. The formula is: EAR = (1 + r/n)^n - 1. For instance, an 8% nominal rate compounded quarterly yields an effective annual rate of 8.24%.

How does compounding frequency impact returns?

The more frequently interest is compounded (e.g. daily vs annually), the higher the final maturity amount, because interest is added to the principal balance sooner and starts earning returns immediately.

What is the Rule of 72?

The Rule of 72 is a mental shortcut to estimate the number of years required to double your money at a constant compound interest rate: Years to Double ≈ 72 ÷ Annual Interest Rate. For example, at 12% p.a., your money doubles in approximately 6 years (72 ÷ 12).

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