How do I calculate monthly compound interest?

Here's how to calculate monthly compound interest using our compound interest formula. Monthly compound interest means that our interest is compounded 12 times per year: Divide your annual interest rate (decimal) by 12 and then add one to it. Raise the resulting figure to the power of the number of years multiplied by 12.

What is a compound interest formula?

The compound interest formula solves for the future value of your investment ( A ). The variables are: P – the principal (the amount of money you start with); r – the annual nominal interest rate before compounding; t – time, in years; and n – the number of compounding periods in each year (for example, 365 for daily, 12 for monthly, etc.).

How do you calculate compound interest on a savings figure?

If you want to roughly calculate compound interest on a savings figure, without using a calculator, you can use a formula called the rule of 72. The rule of 72 helps you estimate the number of years it will take to double your money. The method is simple - just divide the number 72 by your annual interest rate.