Compound Interest Calculator

Calculate how your savings grow with compound interest, regular contributions, and different compounding frequencies.

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See how your money grows over time with compound interest using our free calculator. Enter your principal, rate, and time period to see the power of compounding at work.

How Compound Interest Works

A = P(1 + r/n)^(nt), where P is principal, r is annual interest rate, n is compounding frequency per year, and t is time in years.

How to Use This Calculator

  1. Enter your principal amount
  2. Enter the annual interest rate
  3. Select compounding frequency
  4. Enter the time period
  5. Click Calculate to see your final balance and total interest earned

Frequently Asked Questions

What's the difference between compound and simple interest?

Simple interest only earns on the original principal; compound interest earns on both principal and previously accumulated interest.

Does compounding frequency really matter that much?

Yes, especially over long time periods, daily compounding can meaningfully outperform annual compounding at the same nominal rate.

Can I add regular contributions to this calculator?

Some versions allow monthly contributions on top of the initial principal; check if your specific calculator supports this feature.

Is compound interest good or bad?

It works in your favor when saving or investing, and against you when carrying debt, since interest owed also compounds.