Interest Calculator
Calculate Simple and Compound Interest

Professional interest calculator for both simple and compound interest calculations. Calculate earnings on savings, investment returns, or loan interest costs. Trusted by investors and financial planners for precise interest calculations.

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Interest Calculation Settings

Configure your interest calculation parameters

Interest Calculation Results

Your calculated interest and final amount

Enter valid interest calculation details to see your results

How to Use This Calculator

Master your interest calculations with our comprehensive guide and professional insights.

Enter Principal Amount
Input the initial amount of money you're investing, saving, or borrowing.
Set Interest Rate
Enter the annual interest rate as a percentage for your calculation.
Choose Time Period
Select the duration in years or months for which interest will be calculated.
Select Interest Type
Choose between simple interest (linear growth) or compound interest (exponential growth).
Compounding Frequency
For compound interest, choose how often interest is compounded (daily, monthly, quarterly, or annually).
View Results
See total interest earned or paid, final amount, and growth visualization over time.

Frequently Asked Questions

What is the difference between simple and compound interest?

Simple interest is calculated only on the principal amount and grows linearly. Compound interest is calculated on both the principal and accumulated interest, leading to exponential growth. For example, $1,000 at 10% simple interest earns $100/year, while compound interest earns more each year as interest builds on interest.

How does compounding frequency affect my returns?

More frequent compounding leads to higher returns. Daily compounding earns more than monthly, which earns more than annual compounding. The difference becomes more significant with higher interest rates and longer time periods. This is why APY (Annual Percentage Yield) is often higher than the stated APR.

What is the Rule of 72?

The Rule of 72 is a quick way to estimate how long it takes for money to double. Divide 72 by the interest rate to get the approximate years. At 6% interest, money doubles in about 12 years (72/6=12). This works best for rates between 6-10%.

Should I consider inflation when calculating interest?

Yes, inflation affects the real value of your returns. If you earn 5% interest but inflation is 3%, your real return is only about 2%. For long-term planning, consider using real (inflation-adjusted) interest rates to understand your actual purchasing power growth.

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