Osmolality Calculator

Calculated Osm = (2 × Na) + (glucose / 18) + (BUN / 2.8)
Effective Osm = (2 × Na) + (glucose / 18)
(BUN crosses cell membranes freely and has minimal osmotic effect)
Osmolar gap = Measured Osm – Calculated Osm

Serum Sodium (mmol/L) :

Serum Glucose (mg/dL) :

Serum Urea (mg/dL) :

[Optional] Measured Serum Osmolality (mOsm/kg) :