Compound Interest Calculator
Calculate how investments grow over time with compound interest. See future value, interest earned, and year-by-year growth breakdown.
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$
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Compound Interest Results
- Future Value
- $20,096.61
- Principal + Contributions
- $10,000.00
- Interest Earned
- $10,096.61
- Total Growth
- 101.0% (2.01×)
Principal + Contributions vs. Interest
Principal + Contributions $10,000.00Interest $10,096.61
Rule of 72
At 7% annually, your money doubles approximately every 10.3 years.
Disclaimer: This calculator is for educational purposes. Investment returns are never guaranteed, and past performance does not predict future results.
Compound Interest Formula
A = P(1 + r/n)^(nt). A = final amount. P = principal. r = annual interest rate (decimal). n = compounding periods per year. t = years.
Simple vs. Compound Interest
$10,000 at 5% for 20 years: Simple interest = $20,000. Compound interest (annually) = $26,533. The difference grows dramatically over longer time horizons.
Frequently Asked Questions
- Compound interest is interest calculated on both the initial principal and the interest already accumulated. This creates exponential growth over time.
- Common frequencies: annually (once/year), semi-annually (twice), quarterly (4×), monthly (12×), daily (365×). More frequent compounding means slightly faster growth.
- Divide 72 by your annual interest rate to estimate how many years it takes to double your money. At 6%, money doubles in roughly 12 years (72 ÷ 6 = 12).