Effective Monthly Interest Rate Calculator

I've been researching the past few weeks on ways to put useful calculators in my website. I've tried reading tutorials to encode or embed an interactive calculator in this site. I just recently found out that I can embed spreadsheets using Microsoft excel online. For my first calculator I decided embed one my most used formula in projecting my investments. This calculator will convert annual interest rates to effective monthly interest rate.

Change the annual interest rate in the white box to convert it to compounding monthly rates.