Interest Calculator

Calculate simple and compound interest on loans and investments. Compare different interest calculation methods.

Interest Calculation

Principal Amount ($)

Interest Rate (%)

Time Period (Years)

Compounding Frequency

Additional Monthly Payment ($)

Interest Results

Enter your details and click calculate to see results

Interest Types

• Simple Interest: Interest = Principal × Rate × Time
• Compound Interest: A = P(1 + r/n)^(nt)
• Monthly Payments: Additional contributions each month
• Total Interest: Final amount - Principal - Additional payments

Frequently Asked Questions

What's the difference between simple and compound interest?

Simple interest is calculated only on the principal amount, while compound interest is calculated on the principal plus previously earned interest.

How does compounding frequency affect results?

More frequent compounding (daily vs. annually) results in higher returns due to interest being calculated on previously earned interest more often.

Should I include additional monthly payments?

Yes, if you plan to make regular additional contributions to your investment or extra payments on your loan, include them for a more accurate calculation.