MDCalc Medical Calculator
Mobile App: App Store, Google Play
MedCalcX enables medical professionals to easily calculate medical formulas, scores and classifications. In app purchases available.

Calculate by QxMD
Mobile App: App Store, Google Play
Includes more than 300 different calculators and decision support tools. Calculate such items as ideal body weight, BMI and BSA, due date/gestational age, Kt/V in dialysis patients, eGFR with CKD-EPI, Cockcroft-Gault and MDRD and more.

EBMcalc Complete
Mobile App: iTunes
EBMcalc includes over 600 medical formulae, clinical criteria sets, dose/unit converters and decision tree tools used by health care professionals.

Pepid
Mobile App: A variety of apps available for multiple platforms here.
PEPID gives healthcare professionals all the tools they need to treat patients whether at the scene, en route or at the bedside. Suites are available for physicians, students, residents and more. Includes a large drug database, dosing and medical calculators, high-res pill photos and more.