Critical Care medical calculators
ICU severity scores and organ dysfunction tools.
Critical care scores summarize organ dysfunction, bleeding risk, and illness severity for communication across teams. qSOFA, CURB-65, MAP, anion gap, and resuscitation calculators support—but do not replace—bedside assessment, lactate trends, imaging, and source control. Always document the clinical picture alongside any numeric score.
21 calculators
A–a Oxygen Gradient
A–a GradientCalculate the alveolar–arterial oxygen gradient from ABG values and compare with age-expected normals.
Allowable Blood Loss & EBV
ABL / EBVEstimate blood volume by age group and calculate allowable blood loss before a target hematocrit.
Anion Gap Calculator
Anion GapCalculate serum anion gap with optional albumin correction for acid-base workups.
Bicarbonate Deficit
HCO₃ DeficitEstimate bicarbonate deficit from weight, current HCO₃, and target.
Body Surface Area (BSA)
BSACalculate body surface area with Mosteller, DuBois & DuBois, Haycock, or Gehan & George formulas. Compare all methods side by side.
Burns TBSA & Parkland Formula
Burns / ParklandEstimate percent TBSA with Rule of Nines and calculate Parkland crystalloid resuscitation volumes.
Corrected Calcium
Corrected CaEstimate albumin-corrected serum calcium for hypoalbuminemic patients.
Corrected Phenytoin
PhenytoinAdjust total phenytoin concentration for hypoalbuminemia using the Sheiner–Tozer equation.
Corrected Sodium (Hyperglycemia)
Corrected NaCorrect measured sodium for hyperglycemia using Katz (1.6) or Hillier (2.4) factors.
FENa (Fractional Excretion of Sodium)
FENaCalculate fractional excretion of sodium to help differentiate prerenal from intrinsic AKI patterns.
Free Water Deficit
Free Water DeficitEstimate free water deficit in hypernatremia for replacement planning.
Glasgow Coma Scale (GCS)
GCSScore eye, verbal, and motor responses for rapid neurologic assessment in trauma and critical care.
Ideal Body Weight (Devine)
IBWCalculate Devine ideal body weight, adjusted body weight, and estimated lean body weight.
Infusion Rate (mL/h)
Infusion RateConvert mcg/kg/min or mg/kg/h infusions and bag concentration into mL/h pump rates.
Maintenance Fluids (4-2-1)
Maintenance FluidsEstimate hourly and daily maintenance IV fluid rates with the Holiday–Segar / 4-2-1 rule.
Mean Arterial Pressure (MAP)
MAPCompute mean arterial pressure from systolic and diastolic blood pressure.
MELD-Na Score
MELD-NaCalculate MELD and sodium-adjusted MELD-Na for chronic liver disease severity.
Pediatric ETT Size
Peds ETTEstimate pediatric endotracheal tube internal diameter and approximate oral insertion depth from age.
qSOFA Score
qSOFAQuick bedside screen for patients with suspected infection at higher risk of poor outcomes.
Serum Osmolality & Osmolar Gap
OsmolalityCalculate serum osmolality and optional osmolar gap for toxic alcohol and hyperosmolar workups.
Sodium Deficit
Na DeficitEstimate sodium deficit for hyponatremia replacement planning.