Compound Interest

See how your money grows over time with principal, rate, and compounding frequency

About this calculator

The Compound Interest Calculator shows how your money grows over time when interest is reinvested. Unlike simple interest, compound interest earns returns on your returns — the longer you invest, the faster your balance grows. Enter your principal, rate, compounding frequency, and time to see your investment's future value.

How to use the Compound Interest calculator

  1. Enter your amounts, rates and terms into the input fields.
  2. Read the result — it updates instantly as you type.
  3. Adjust the inputs to compare scenarios side by side.
  4. Copy the page URL to share the exact calculation.

Common examples

  • $1,000 at 5% annually for 10 years → future value $1,628.89, interest earned $628.89
  • $5,000 at 7% compounded monthly for 20 years → future value $20,097.11, interest $15,097.11
  • $10,000 at 3% compounded daily for 5 years → future value $11,618.22, interest $1,618.22
  • $500 at 10% compounded quarterly for 30 years → future value $8,935.05, total growth 1,687%
  • $100,000 at 4% semi-annually for 15 years → future value $181,136.16, interest $81,136.16

Frequently asked questions

How does the Compound Interest calculator work?

Enter your amounts, rates and terms, and the calculator applies the standard financial formulas to show the outcome, including intermediate figures where they help you understand the result. All arithmetic runs at high precision, so rounding errors do not build up across periods.

When would I use the Compound Interest calculator?

Use it when planning a purchase, loan, investment or budget, to compare options before committing, or to sanity-check figures quoted to you. It is an educational tool, not financial advice — confirm important decisions with your provider or a professional.

How accurate are the results?

The formulas are the standard ones used in finance and run at 30 significant digits internally. Real products may differ in fees, compounding conventions and rounding rules, so treat the result as a close estimate rather than a contractual figure.

Can I share a specific calculation with someone else?

Yes. Every value you enter updates the URL, so copying the address bar and sharing the link reopens the exact same calculation for whoever clicks it.