Compound Interest Calculator
See how your investments grow over time with the power of compound interest. Enter your principal, expected return rate, and monthly contributions to project your wealth.
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Why Compound Interest Is the Key to Building Wealth
Albert Einstein reportedly called compound interest the eighth wonder of the world. Here is why it matters for every investor.
Exponential Growth
Your money earns returns on previous returns, creating a snowball effect that accelerates over time. The longer you stay invested, the more dramatic the growth curve becomes.
Time Is Your Ally
Starting early matters more than investing large amounts later. Even small, consistent contributions can grow into substantial wealth given enough compounding periods.
Consistency Wins
Regular monthly contributions combined with compound interest create a powerful wealth-building engine. Dollar-cost averaging smooths out market volatility over time.
Frequently Asked Questions
What is compound interest?
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, which only earns interest on the original amount, compound interest allows your money to grow exponentially over time as you earn interest on your interest.
How does compounding frequency affect my returns?
The more frequently interest compounds, the more you earn. Daily compounding yields slightly more than monthly, which yields more than quarterly, and so on. However, the difference between daily and monthly compounding is relatively small compared to the difference between annual and monthly compounding.
What is the Rule of 72?
The Rule of 72 is a simple formula to estimate how long it takes for an investment to double. Divide 72 by the annual interest rate to get the approximate number of years. For example, at 8% annual return, your money doubles in roughly 9 years (72 / 8 = 9).
How accurate is this compound interest calculator?
This calculator provides a mathematical projection based on a fixed rate of return and regular contributions. Real-world investments experience variable returns, fees, taxes, and market fluctuations that this calculator does not account for. Use it as an educational planning tool, not a guarantee of returns.
Why is starting early so important for compound interest?
Time is the most powerful factor in compound interest. The earlier you start, the more compounding periods your money goes through. Someone who invests $200/month starting at age 25 will typically accumulate significantly more than someone who invests $400/month starting at age 35, even though the late starter contributes more total money.
Go Beyond Calculations
Use Investment Architect to analyze your real portfolio, detect concentration risks, get AI-powered allocation insights, and receive weekly performance reports.