Why Compounding Matters
Compounding becomes more powerful as time grows because each period's earnings can generate future earnings. Starting earlier can matter as much as increasing contribution size.
Compound Interest Calculator
Estimate future value from starting principal, annual return, compounding frequency, time, and recurring contributions.
Compound Interest Formula
A = P(1 + r/n)^(nt)Compound interest means interest earns additional interest over time. The calculator also adds recurring contributions at the selected compounding interval to estimate long-term growth.
| Symbol | Variable | Description |
|---|---|---|
| A | Future value | Estimated ending balance. |
| P | Principal | Starting amount before growth. |
| r | Annual rate | Annual return or interest rate as a decimal. |
| n | Compounding frequency | Number of times interest compounds per year. |
How to Use the Compound Interest Calculator
- 1
Enter starting amount
Add the principal you have today.
- 2
Set rate and time
Enter an annual return or interest rate and the number of years.
- 3
Add contributions
Use recurring contributions to model regular saving or investing.
Contributions vs Interest Earned
The calculator separates total contributions from interest earned so you can see how much of the future value comes from your savings versus growth.
Planning With Realistic Rates
Use conservative rates for planning. Savings accounts, bonds, and stock portfolios have different risk and return patterns, and past returns do not guarantee future results.
Compound Interest Calculator FAQ
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