Compound Interest Calculator
See how savings or investments grow over time with compound interest and optional monthly contributions.
What Is the Compound Interest Calculator?
The Compound Interest Calculator projects how an initial amount grows when interest compounds over time, with optional regular monthly contributions. Set the principal, annual rate, number of years, how often interest compounds, and any monthly deposit to see the future value, the total you put in, and the interest earned. Everything is computed locally.
How It Works
Enter your starting principal, the annual interest rate, the number of years, the compounding frequency and an optional monthly contribution. The future value and breakdown update instantly.
When to Use It
Use it to plan savings goals, estimate investment growth, compare accounts with different compounding, or see the long-term power of regular contributions.
Frequently Asked Questions
- What does compounding frequency change?
- How often interest is added to the balance. More frequent compounding (e.g. monthly vs annually) earns slightly more, because each new balance earns interest sooner.
- Are the projections guaranteed?
- No. They assume a constant rate and regular contributions. Real returns vary, so treat the result as an estimate for planning.
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