Anesthesia & perioperative calculators
Interactive clinical calculators with the formula, interpretation, and references — free. Looking for drugs instead? Drug dosing reference →
Cardiac & Risk
Revised Cardiac Risk IndexEstimates perioperative cardiac risk for non-cardiac surgery.CHA₂DS₂-VASc ScoreStroke risk in atrial fibrillation — guides perioperative anticoagulation bridging decisions.MELD-Na ScoreModel for End-Stage Liver Disease — predicts perioperative mortality in hepatic patients.Duke Activity Status IndexEstimates functional capacity in METs for perioperative cardiac risk assessment.Caprini VTE Risk ScoreEstimates venous thromboembolism risk in surgical patients.Mean Arterial PressureCalculates MAP from systolic and diastolic blood pressure.
Pulmonary
Renal & Electrolytes
Creatinine Clearance (Cockcroft-Gault)Estimates GFR for drug dosing adjustments — essential for renally-cleared anesthetic agents.Corrected CalciumAdjusts serum calcium for albumin level.Corrected Sodium for HyperglycemiaAdjusts sodium for the dilutional effect of hyperglycemia.Serum Osmolality GapDetects unmeasured osmoles (toxic alcohols, propylene glycol).Fractional Excretion of SodiumDifferentiates prerenal AKI from intrinsic renal injury.
Critical Care
Glasgow Coma ScaleStandardized assessment of consciousness level — guides intubation and neuroprotective management.Sequential Organ Failure AssessmentTracks organ dysfunction severity in critically ill patients.Quick SOFARapid bedside sepsis screen — no lab values needed.Parkland Formula (Burn Resuscitation)Fluid resuscitation for burn patients — essential for OR burn cases.
Anesthesia-Specific
QTc Interval CorrectionCorrects QT interval for heart rate — critical for drug-induced QT prolongation assessment.Opioid Equianalgesic ConversionConverts between opioids using morphine milligram equivalents (MME).Maintenance Fluid Rate (4-2-1)Calculates hourly maintenance fluid requirements using the Holliday-Segar method.