Compound Interest Calculator
See how your money grows over time with the power of compounding
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Compound Interest Formula
A = P(1 + r/n)^(nt)
- A = Final amount
- P = Principal
- r = Annual rate (decimal)
- n = Compounding frequency per year
- t = Time in years
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Guide
How it works
Compound interest means you earn interest on your interest — making your money grow exponentially over time. The more frequently it compounds, the faster it grows.
Formula: A = P(1 + r/n)^(nt)
What is the difference between simple and compound interest?expand_more
Simple interest is calculated only on the principal. Compound interest is calculated on the principal plus accumulated interest, so it grows faster over time.
How often should interest compound?expand_more
More frequent compounding means more growth. Daily compounding earns slightly more than monthly, which earns more than annually.
What is the Rule of 72?expand_more
Divide 72 by your annual rate to estimate how many years it takes to double your money. At 8%, money doubles in approximately 9 years.
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