Compound Interest Calculator
Future Value
$54,713.58
Total Contributions
$34,000.00
Total Interest Earned
$20,713.58
Growth Over Time
How it works
The compound interest calculator shows how an investment could grow when the interest it earns is added back and starts earning interest too. Enter a starting amount, a monthly contribution, an annual interest rate, a number of years (up to 50) and how often interest compounds: annually, semi-annually, quarterly, monthly or daily.
The calculator steps through each compounding period. In every period, the balance grows by the annual rate divided by the number of periods per year, and then your contributions for that period are added. Contributions are spread to match the compounding schedule, so with monthly compounding your full monthly amount is added each month, while with annual compounding twelve months of contributions are added at the end of each year. Without contributions, this matches the standard formula A = P x (1 + r/n)^(nt).
The results show the future value, the total you put in (starting amount plus all contributions) and the interest earned, which is the difference between the two. The chart compares your balance with your contributions year by year. Real returns change from year to year and may be reduced by fees, taxes and inflation, which this calculator doesn't include. Results are illustrations, not financial advice. Amounts are shown in the currency you pick, which starts as the one for your region; the math is the same in any currency.
Frequently asked questions
What is compound interest?+
Compound interest is interest earned on both your original money and the interest it has already earned. Over time this makes growth speed up, which is why the balance line on the chart curves upward.
How is compound interest calculated?+
Without contributions, the future value is P x (1 + r/n)^(nt), where P is the starting amount, r the annual rate, n the number of compounding periods per year and t the number of years. This calculator applies that growth period by period and adds your contributions along the way.
Does compounding more often make a big difference?+
It helps a little. At the same annual rate, daily compounding earns slightly more than monthly, and monthly slightly more than annually, but the rate and the time invested matter much more.
How much will $10,000 grow in 10 years?+
It depends on the rate. At 7% a year compounded monthly with no extra contributions, $10,000 grows to about $20,097. Enter your own numbers to see the result.