Compound Interest Calculator
Global Finance
Compound interest calculator
Enter principal, annual rate, compounding frequency, and time to project future value and accumulated interest.
Compound Interest
Amount
$1,050.00
Interest
$50.00
Compounds/year
1
How calculations work
All calculations are performed locally in your browser and no data is sent to external services.
- Principal (P): initial amount entered.
- Rate (r): annual percentage (entered as %), converted to decimal for calculations.
- Compounds per year (n): how many times interest is applied per year.
- Time (t): number of years.
- Future value: computed as P × (1 + r/n)^(n×t). Interest = Future value − P.
Results are rounded for display. This calculator assumes periodic compounding and fixed rate.
What this calculator does
This Compound Interest Calculator projects how an investment or savings balance grows over time when interest is applied periodically. Provide the initial principal, annual interest rate, compounding frequency, and the time horizon to see future value and accumulated interest.
Who should use this calculator
Use this if you want to understand the effect of compound interest on savings, investments, or loan growth. It is suitable for students, savers, and planners comparing frequencies (annual vs monthly) or testing different contribution scenarios.
How this calculator works
The calculator uses the standard compound interest formula: Future Value = Principal x (1 + r/n)^(n x t), where r is the annual rate (as a decimal), n is compounds per year, and t is years. All calculations run locally in your browser — no data is sent to any server.
How to interpret the results
Results show the projected account value and total interest earned. Compare outcomes by changing rate, frequency or time: longer horizons and more frequent compounding increase growth. This is a projection based on the inputs and assumes rates remain constant.
Example
A $10,000 principal at 5% APR compounded monthly for 10 years will grow more than at annual compounding. The calculator shows the numeric difference so you can quantify the benefit of compounding frequency.
Limitations & disclaimer
This is a mathematical projection that ignores taxes, fees, inflation, and changing rates. Use it for planning and comparison only. For localized formatting or regulation, see the calculators hub.
Frequently asked questions
What is compound interest?
Compound interest is interest calculated on the initial principal and also on the accumulated interest from previous periods. It makes savings grow faster than simple interest over time.
How does compounding frequency affect growth?
More frequent compounding (e.g., monthly vs annually) means interest is applied more often, resulting in slightly higher total returns. The difference is most noticeable over long time horizons.
Is this calculator accurate for real investments?
This calculator uses the standard compound interest formula and assumes a constant rate. Real investments may have variable rates, fees, and taxes that change the outcome.
Can I compare simple and compound interest?
Yes. Use this calculator alongside the simple interest calculator with the same inputs to see how compounding accelerates growth.