A medical calculator is a type of medical computer software, whose purpose is to allow easy calculation of various scores and indices, presenting the user with a friendly interface that hides the complexity of the formulas. Most offer further helpful information such as result interpretation guides and medical literature references.[1] Generally, such calculators are intended for use by health care professionals, and use by the general public is discouraged.[citation needed]
Medical calculators arose because modern medicine makes frequent use of scores and indices that put physicians' memory and calculation skills to the test.[2] The advent of personal computers, the Internet and Web, and more recently personal digital assistants (PDAs) have formed an environment conducive to their development, spread and use.
Purpose-built devices for specific medical calculations are available from various commercial sources. Pharma-Insight Inc. in Canada is one of the only companies in the world that is able to make custom specific medical calculators built to perform a specific medical calculation to make dosing or other calculation easy.[promotion?] Some of the standard units they make include eGFR, CrCl, BMI, BSA, DAS and many other custom units designed for a specific purpose. There are two ways to make a calculator using an array that looks up an answer based on a large array of data or where the calculator computes the answer using a mathematical equation.[citation needed]
Software-based medical calculators are available for various PDA-platforms, including the iPhone, Palm and Pocket PC. Handheld battery powered portable units are available and can be manufactured in smaller quantities than before thanks to OTP (one Time Programmable) chips.[3][citation needed]
Various websites are available that provide calculations from a browser based input form.