Compound Interest Calculator

Calculate how your investment grows with compound interest. Set your principal, rate, time, and compounding frequency for instant results.

How To Calculate Compound Interest

1
Enter Principal and Rate

Enter your initial investment amount and annual interest rate percentage.

2
Set Time and Frequency

Enter the investment duration in years and select the compounding frequency.

3
View Results

Click Calculate to see final amount, total interest earned, and total growth percentage.

About the Compound Interest Calculator

The ToolCentrix Compound Interest Calculator helps investors, students, and financial planners calculate how an investment grows over time using the power of compounding. Compound interest earns returns not just on your principal but also on the interest already accumulated — making it the most powerful force in long-term wealth creation.

The compound interest formula: A = P × (1 + r/n)^(n×t), where A is the final amount, P is the principal, r is the annual interest rate as a decimal, n is the compounding periods per year, and t is the time in years. The compound interest earned is A − P.

Compounding frequency matters: The more frequently interest is compounded, the faster your money grows. Monthly compounding yields more than annual compounding at the same rate. This calculator supports annual, semi-annual, quarterly, monthly, and daily compounding so you can see exactly how frequency affects returns.

The Rule of 72: A quick mental shortcut — divide 72 by the annual interest rate to estimate how many years it takes to double your money. At 8% annual compounding, your investment doubles in approximately 9 years. At 12%, it doubles in 6 years.

Compound interest vs simple interest: On ₹1,00,000 at 10% for 10 years: simple interest gives ₹1,00,000 in interest. Compound interest (monthly) gives approximately ₹1,70,700 in interest — 70% more. The difference grows dramatically over longer periods.

All calculations are performed instantly in your browser. No data is sent to any server. Free to use with no sign-up required.

Frequently Asked Questions

What is compound interest? +
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. It grows exponentially over time, making it more powerful than simple interest for long-term investments.
What is the compound interest formula? +
A = P × (1 + r/n)^(n×t), where A is the final amount, P is the principal, r is the annual interest rate (as a decimal), n is the compounding periods per year, and t is time in years.
What is the difference between simple and compound interest? +
Simple interest is calculated only on the principal each period. Compound interest is calculated on the principal plus accumulated interest, causing faster exponential growth over time.
How does compounding frequency affect returns? +
More frequent compounding means higher returns. Monthly compounding yields more than annual compounding at the same rate because interest is added to the principal more often, earning more interest in turn.
What is the Rule of 72? +
Divide 72 by the annual interest rate to estimate how many years it takes to double your money. At 8% compound interest, money doubles in approximately 9 years (72 ÷ 8 = 9).

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