Plasma Osmolality Calculator

Free calculate plasma osmolality. This is an educational tool only - always consult a healthcare provider.

Laboratory Values

Results

Enter lab values to calculate osmolality

About Plasma Osmolality

  • • Osmolality = 2 × Na + Glucose/18 + BUN/2.8
  • • Normal: 275-295 mOsm/kg
  • • High: Dehydration, hyperglycemia
  • • Low: Overhydration, SIADH
  • • Osmolar gap = Measured - Calculated