InterestMath

Compound Interest Calculator

Calculate how your money grows with compound interest over time. See year-by-year breakdowns with interactive charts.

Calculator InputsReal-time

Final Balance

$20,096.61

Total Interest Earned

$10,096.61

Total Contributions

$10,000

Your money earned 101.0% return on your total contributions over 10 years — that's $10,096.61 in free money from compound interest
Balance Growth Over Time
How Compound Interest Works

Compound interest is one of the most powerful forces in finance. Unlike simple interest, which only earns returns on your original principal, compound interest earns returns on both your principal and previously earned interest. This creates an exponential growth curve that accelerates over time.

The Compound Interest Formula

A = P(1 + r/n)nt

  • A = Final amount (principal + interest)
  • P = Principal (initial investment)
  • r = Annual interest rate (as a decimal, e.g. 0.07 for 7%)
  • n = Number of times interest is compounded per year
  • t = Number of years

Example Calculation

If you invest $10,000 at 7% annual interest, compounded monthly, for 10 years:

A = 10,000 (1 + 0.07/12)^(12 x 10)

A = 10,000 (1.005833)^120

A = 10,000 x 2.0097

A = $20,096.61

You would earn $10,096.61 in interest, nearly doubling your initial investment with no additional contributions.

The Power of Regular Contributions

Adding regular monthly contributions dramatically accelerates growth. Using the same example above but adding $200/month, your balance after 10 years would be approximately $54,780 — with $34,000 in contributions and over $20,000 in interest earned. The combination of compound interest and consistent contributions is the foundation of long-term wealth building.

Frequently Asked Questions

This calculator is for educational purposes only and does not constitute financial advice. Consult a qualified financial advisor for personalized guidance.