Anion Gap + Osmolality + Osmolar Gap
Calculator with US (conventional) and SI (European) units. Units are shown beside each input.
US / Conventional
SI / European
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Calculate
Inputs
Electrolytes
Sodium (Na)
mEq/L
Chloride (Cl)
mEq/L
Bicarbonate (HCO₃ / CO₂)
mEq/L
Albumin (optional)
g/dL
Osmolality
Glucose
mg/dL
BUN
mg/dL
Urea
mmol/L
Ethanol (optional)
mg/dL
Measured Osmolality
mOsm/kg
AG = Na − (Cl + HCO₃)
US osmolality uses:
2×Na + glucose/18 + BUN/2.8 (+ ethanol/3.7)
SI osmolality uses:
2×Na + glucose + urea (+ ethanol)
Results
Anion Gap
—
mEq/L
Need Na, Cl, HCO₃
Corrected Anion Gap
—
mEq/L
Albumin optional
Calculated Osmolality
—
mOsm/kg
Need Na, glucose, BUN/urea
Osmolar Gap
—
mOsm/kg
Need measured osmolality
Differential diagnosis
—
created by Nick Mark
@nickmmark