BMI (and a BMI Calculator for Google)
I tend to make patients who are morbidly obese (BMI over 40) ASA physical status III after my pre-anesthetic assessment. I do this because, well, everything is harder with morbidly obese patients. To support that assignment on the anesthesia record, I like to write the actual BMI as a justfication. I needed a quick way to calculate it and asked Seth Dillingham to write a Google module I can have quick access to for this calculation. There's a nice feature that if you fill in the values in one system (say, US), clicking on the other tab will show the corresponding values in the other system (say, metric).