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Compound Interest Calculator

Free compound interest calculator: see how your investments grow over time with daily, monthly, or yearly compounding. Calculate future value, total interest, and plan your retirement savings.

The compound interest calculator shows how your investments grow over time with the power of compounding. Compounding means your investment earns returns on both the original principal and previously earned returns — creating exponential growth.

This calculator supports different compounding frequencies (daily, monthly, quarterly, annually) and regular monthly contributions. Use it to compare investment strategies, understand the impact of compound frequency, and plan for long-term financial goals. The growth chart visualizes how your balance, contributions, and earnings change over time.

$
$
7%
0.130
10years
150
Example
Example: Invest $10,000 for 20 Years at 7%

Set Principal to $10,000, Rate to 7%, Years to 20, Monthly Contribution to $500, and Compound to Monthly.

The calculator shows:
• Future Value: ~$300,000 (estimated)
• Total Interest Earned: ~$170,000
• Total Contributions: $130,000 ($10,000 + $500 × 240 months)

Key Insight: The power of compound interest means more than half of your final balance comes from investment returns, not your contributions. Starting early and contributing consistently are the two most important factors.

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 accelerates growth over time.

How does compound frequency affect my returns?

More frequent compounding periods (daily vs. annual) generate higher returns because interest is calculated on interest more often. Daily compounding yields slightly more than monthly or annual compounding.

What is the Rule of 72?

The Rule of 72 is a quick way to estimate how long an investment takes to double. Divide 72 by your annual interest rate. For example, at 8% interest, it takes approximately 72/8 = 9 years to double your money.

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