Imagine that instead of compounding the interest every day, you wanted to calculate it every nanosecond. And then, every billionth of a nanosecond. If you keep dividing that until it’s an infinite number of infinitely small compounding, you get a super simple equation:

  interest = e^(years*rate)

10% interest for 5 years?

  e^(5*.1) = 1.649

3% for 8 years?

  e^(8*.03) = 1.271

You can plug any numbers into that and get the end result in 1 step.