Compound Interest Calculator – Daily, Monthly & Annual Growth
Calculate how compound interest grows your savings over time with this free tool. Compare daily, monthly, quarterly, and annual compounding frequencies. See a detailed breakdown of your principal versus earned interest, year by year.
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yr
Your Results
Total Contributions
$130,000
Total Interest Earned
$134,122
Final Balance
$264,122
Frequently Asked Questions
How does compound interest work?
Compound interest is interest earned on both your initial principal and the accumulated interest from previous periods. It is often described as "interest on interest" and can cause your savings to grow exponentially over time. The more frequently interest compounds, the faster your money grows.
What is the difference between daily and monthly compounding?
Daily compounding means interest is calculated and added to your balance 365 times per year, while monthly compounding does this 12 times per year. Daily compounding yields slightly higher returns — for example, $10,000 at 5% for 20 years grows to about $27,183 with daily compounding vs $27,126 with monthly compounding.
How much should I contribute each month?
Even small monthly contributions add up significantly over time thanks to compound interest. For example, investing just $100 per month at a 7% annual return grows to over $121,000 in 30 years (with $36,000 of that being your contributions and $85,000 being interest). The key is consistency and starting early.
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How to Use the Compound Interest Calculator
- Enter your initial investment — the starting amount you have saved.
- Set your monthly contribution — how much you plan to add each month.
- Choose your expected interest rate — 7% is the historical S&P 500 average after inflation.
- Select compounding frequency — daily compounding grows your money fastest.
- Adjust the time horizon — longer time = more powerful compounding.
The stacked area chart shows your principal (bottom) and interest earned (top). Notice how the interest portion grows larger than contributions over long time horizons — that is compound interest at work.