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Calculations shouldn't be used alone for patient care, and don't substitute for professional judgment. See our full disclaimer.

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Frequently Asked Questions

What is

This is a site for medical professionals to help us do calculations and process algorithms and scores. To make patients better. Faster. You can access the full list through the navigation bars, or, preferably, through the search menu.

How do I get an answer? There’s no button to click!

Once you’re done entering numbers, click anywhere off the entry box or just hit tab. Not until I saw some residents use the site did I realize people enter data into web browsers differently from me, and I didn’t realize this might be a problem–once you get used to it, however, I think it’s a much quicker and more friendly system.

How do units work?

The site should auto-detect what country you’re visiting the site from (the US, or everywhere else) and determine the correct units for your country by default. If it doesn’t work, simply click the desired units you want in the upper-right hand corner of the equation page, and the site will remember this preference.

What browsers are supported?

We now support IE8+ as well as recent versions of Safari, Firefox, Chrome, and Opera. Users of IE6 and IE7 will be directed to our old site (

Can you add [this equation]?

Sure. Email me and I’ll get right on it. It’ll happen much faster if you can provide me with a reference and the equation/rule, since I need to double-check it to ensure it’s accurate.

Who is

This site was created by Graham Walker, MD, who got tired of having to wade through Google searches to find an easy to use, quick calculator for the medical equations his residents were pimping him on (on which he was being pimped?). Many thanks to the multiple resources and references I’ve used to put this list together.

Graham is now an Emergency Physician at Kaiser San Francisco, after having completed a Simulation Medicine fellowship at the Stanford University School of Medicine in the Division of Emergency Medicine, with residency at St. Luke’s-Roosevelt Hospital Center in New York City.

Most recently, Graham has partnered with former co-resident and colleague Joe Habboushe, MD to develop MDCalc further, forming MD Aware, LLC.

Calculations must be re-checked and should not be used alone to guide patient care nor should they substitute for clinical judgement. See our full disclaimer.