For fun, I created this compound interest calculator with a chart. Just enter your values in the form below the chart, hit submit, and it will display your results.

Caveats:

Rounds to the nearest penny using Math.round(num * 100) / 100

Period is a number from 1 (yearly) to 365 (daily). Use 12 for monthly, 52 for weekly.

Quick story: I used to think that if you had a savings account at 10%, you got 10% interest everytime it was calculated. Therefore it made sense to me that interest compounded daily would make 365 times that calculated once a year. As it turns out, interest compounded daily would get 1/365th the annual interest daily, and monthly would get 1/12th the annual interest monthly.

Check out the source here.