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Compound Interest Rate Calculator

Enter your principal, final balance, and the number of years to instantly back-calculate the annual compound interest rate. See at a glance what rate your investment or savings actually grew at, along with the total interest earned.

Input

$
$
yr

Result

Annual rate (annual compounding, 10-year term)

4.137974%

Principal

$1,000,000.00

Final amount

$1,500,000.00

Interest

$500,000.00

How it works

  • Enter the principal, final amount, and investment period, and the tool back-calculates the annual rate assuming annual compounding.
  • The formula is r = (final amount / principal)^(1 / years) - 1, and the resulting r is multiplied by 100 to display as an annual percentage.
  • Annual compounding means interest is added to the principal once a year, and the following year's interest is earned on that combined balance. This tool assumes compounding once per year.
  • Interest is calculated as "final amount - principal," and the principal, final amount, and interest are each shown on a separate card.
  • The rate is displayed to about six decimal places, so you can check a precise yield from your actual results. Enter a principal and final amount greater than 0, and a period of 1 to 100 years.
  • Note: the calculated rate is a theoretical value that ignores taxes, fees, additional contributions, and withdrawals. It does not guarantee actual yields or investment results.