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Compound Interest Calculator

See how your savings or investments grow over time with compound interest. Supports monthly contributions, different compounding frequencies, and inflation adjustment.

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Growth over time

Frequently asked questions

What is compound interest?

Compound interest is interest earned on both your initial principal and the interest that has already accumulated. It causes your savings to grow exponentially over time, Einstein allegedly called it "the eighth wonder of the world."

How often should interest compound?

More frequent compounding yields slightly more growth. Daily compounding on a 7% rate earns about 0.05% more per year than annual. It matters more at higher rates and longer terms.

What rate of return should I use?

Historically, a diversified S& 500 index fund has averaged about 10% nominal annual return before inflation, or ~7% after inflation. High-yield savings accounts currently pay 4-5%. Use a conservative estimate.

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