Compound Interest Calculator
Project how an investment grows over time when interest is earned on both the principal and previously accumulated interest.
$6470.09
Interest earned
$16470.09
Total value
About the Compound Interest Calculator
A compound interest calculator projects how an investment grows over time when interest is earned not just on the principal but also on previously accumulated interest.
The compound interest formula
A = P × (1 + r/n)^(n×t)
A= final balance
P= principal (starting amount)
r= annual interest rate, as a decimal
n= number of times interest compounds per year
t= number of years
Effect of compounding frequency
| Compounding | Balance after 10 years | |
|---|---|---|
| Annually | $1,000 → $1,628.89 | |
| Monthly | $1,000 → $1,819.40 | |
| Daily | $1,000 → $1,822.03 |
How to use
1
Enter your principal amount, interest rate, and time period.
2
Choose how often interest compounds, such as monthly or annually.
3
View the projected final balance and total interest earned.
Worked examples
Example calculation
$5,000 invested at 6% annual interest, compounded monthly, for 15 years.
Input
P = $5,000, r = 0.06, n = 12, t = 15
Result
Final balance ≈ $12,230
That's roughly $7,230 in growth, more than a simple-interest calculation would produce because interest is earned on previously accumulated interest too.
Frequently asked questions
How does compounding frequency affect the result?
More frequent compounding, such as monthly instead of annually, results in slightly higher total growth for the same stated interest rate.
What's the difference between compound and simple interest?
Simple interest is calculated only on the original principal, while compound interest is calculated on the principal plus any interest already earned, leading to faster growth over time.
Explore more tools in the Calculators category.