Compound Interest Calculator
See how your savings grow with compound interest. Add optional monthly contributions and choose the compounding frequency.
About This Free Online Compound Interest Calculator
Our free compound interest calculator shows how your money grows over time. Enter a starting principal, annual rate, and number of years, choose how often interest compounds (annually, quarterly, monthly, or daily), and optionally add a recurring monthly contribution. The tool instantly shows your final balance, total contributions, and total interest earned — the power of compounding made clear. All math runs in your browser. Perfect for planning savings, investments, and retirement goals.
Features of Our Compound Interest Calculator
- Final balance, total contributions, and interest earned
- Optional recurring monthly contributions
- Annual, quarterly, monthly, or daily compounding
- Shows the growth from compounding clearly
- Live results as you type
- 100% private — browser-only processing
How to Use the Compound Interest Calculator
The Compound Interest Calculator works right in your browser — no signup, no installation. Follow these steps:
- Enter your starting principal, annual rate, and years.
- Optionally add a monthly contribution.
- Choose how often interest compounds.
- Read your final balance and total interest earned.
Frequently Asked Questions About Compound Interest Calculator
What is the compound interest formula?
For a lump sum it is A = P(1 + r/n)^(nt), where P is the principal, r is the annual rate (as a decimal), n is the number of times it compounds per year, and t is the years. When you add monthly contributions, the tool compounds monthly and adds the future value of those deposits.
How does compounding frequency affect growth?
More frequent compounding earns slightly more, because interest is added to the balance more often and then itself earns interest. Daily compounding beats annual, though the difference is usually small.
Are monthly contributions before or after interest?
This calculator adds each monthly contribution and then compounds, treating deposits as ongoing. It is a close model for regular saving into an interest-bearing account.
Why Choose the Compound Interest Calculator?
The Compound Interest Calculator is built for answers you can rely on, not rough guesses. Every calculation happens locally in your browser the moment you enter a value, so results are immediate, the math is transparent, and nothing you type ever leaves your device.