The purpose of this App is to provide, not just a calculator of a given formula, but rather engage in a comprehensive explanation in a succinct manner that explains the Formula, Concept, Clinical Utility, Interpretation, and Limitations and Caveats of each formula with an Example that illustrates the clinical utility of the formula and its limitations. In a way, the idea is to provide the type of discussion that one used to have with residents and fellows on a blackboard when the time and circumstances allowed this type of interaction, which is less and less seen with the change and rapid pace of teaching rounds in medicine. Additionally, a few References are provided for further reading.