Compound Interest Calculator
Calculate compound and simple interest, compare growth, and visualize your savings over time.
This free compound interest calculator shows how your money grows when interest compounds daily, monthly, quarterly, or annually. Add regular contributions to see your total savings, interest earned, and a year-by-year growth breakdown.
Investment Parameters
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How to Use
1
Enter Your Principal
Input the initial amount of money you plan to invest or save.
2
Set the Interest Rate
Enter the annual interest rate offered by your bank or investment.
3
Choose Time & Frequency
Select the investment duration in years and how often interest compounds.
4
Add Monthly Contributions
Optionally add a monthly deposit amount to see how regular savings accelerate growth.
5
Review Results
Click Calculate to see your results with comparison charts, tables, and frequency breakdowns.
Frequently Asked Questions
What is the difference between simple and compound interest?
Simple interest is calculated only on the original principal. Compound interest is calculated on the principal plus all previously accumulated interest, making your money grow faster over time.
How does compounding frequency affect my returns?
The more frequently interest compounds, the more interest you earn. Daily compounding yields slightly more than monthly, which yields more than annually, because interest starts earning interest sooner.
What is the Rule of 72?
The Rule of 72 is a quick mental math shortcut. Divide 72 by your annual interest rate to estimate how many years it takes to double your money. For example, at 6% interest, it takes approximately 12 years.
Are the calculations accurate for real investments?
This calculator provides mathematical estimates based on a fixed interest rate. Real investments may have variable rates, fees, taxes, and other factors. Use these results as a starting point for planning.
How do monthly contributions impact compound interest?
Regular monthly contributions dramatically increase your final balance because each deposit also earns compound interest. Even small monthly amounts can make a huge difference over long periods due to the snowball effect.