Compound Interest Calculator

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Calculate how your investment grows with compound interest over time. Enter your principal amount, annual interest rate, time period, and compounding frequency to see your final balance and interest earned.

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Enter Your Measurements

Results

Final Amount

16,470.09

$

Interest Earned

6,470.09

$

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Formula

A = P(1 + r/n)^(nt), where A = final amount, P = principal, r = annual rate, n = compounds per year, t = years

How to Use This Calculator

How to Use

  1. 1

    Enter your initial investment amount (principal).

  2. 2

    Enter the annual interest rate offered by your account or investment.

  3. 3

    Enter the time period in years.

  4. 4

    Select how often interest compounds (monthly is most common).

  5. 5

    View your final balance and total interest earned.

Frequently Asked Questions

Frequently Asked Questions

What is compound interest?

Compound interest is interest earned on both your principal and previously earned interest. It causes investments to grow faster than simple interest because you earn interest on your interest.

How often should interest compound?

More frequent compounding (daily vs. annually) results in slightly higher returns. Banks often compound daily or monthly. The difference is small with lower interest rates but becomes significant with higher rates.

How long does it take to double my money?

Use the Rule of 72: divide 72 by your interest rate to estimate years to double. For example, at 6% interest, 72 ÷ 6 = 12 years to double.
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About This Calculator

This calculator uses the formula: A = P(1 + r/n)^(nt), where A = final amount, P = principal, r = annual rate, n = compounds per year, t = years. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.

Built and maintained by the CalcSmart team. Last updated March 2026.

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