Compound Interest Calculator - Investment Growth | Financial Calculator

Free compound interest calculator to compare compound vs simple interest growth. Choose compounding frequency and see your investment grow over time.

How to Use

  1. Initial Investment — Enter the amount you plan to invest initially
  2. Annual Interest Rate — Enter the expected average annual return rate (%)
  3. Investment Period — Enter how long you plan to invest in years or months
  4. Compounding Frequency — Choose monthly, quarterly, semi-annual, or annual compounding
  5. Calculate — Click Calculate to see compound and simple interest results and the difference

FAQ

Why does compound interest matter more than simple interest?

Compound interest earns returns on previously earned interest, creating exponential growth. The longer the investment period, the more dramatically it outpaces simple interest.

Does more frequent compounding give better results?

Yes — monthly compounding outperforms quarterly, which outperforms annual. More frequent compounding means interest is reinvested sooner, leading to higher final returns.

What is the Rule of 72?

Divide 72 by the annual interest rate to estimate years to double your money. Example: at 6% annual return, 72÷6 = 12 years to double. A handy rule for long-term planning.