There are many options but at this time Medcalc is my go-to calculator .
MedCalc runs on Palm OS and Windows Mobile handheld devices. It is designed for rapid calculation of common medical formulas and scores used in anesthesiology, pediatrics, emergency, intensive care and internal medicine.
- free and easy to use
- comprehensive (>80 formulas, see complete list)
- formulas sorted by categories
- units available either in S.I. or local units (defaults can be set for each item)
- most formulas come with bibliographic references and clinical tips
- results can be saved for later retrieval (Palm OS only)