Serum Osmolality (Calculated)
Conventional estimate: 2×Na + Glucose/18 + BUN/2.8 (mg/dL).
Calculator
How it works
This page applies a widely taught linear estimate from routine chemistry. It does not replace laboratory osmometry or clinical toxicology pathways.
Calculated osm ≈ 2×[Na] + [Glucose]/18 + [BUN]/2.8 (mg/dL for glucose and BUN)
Limits
Does not include ethanol or other osmoles; severe hyperproteinemia/lipids affect sodium measurement (pseudohyponatremia) and interpretation.
Educational tool only—not for diagnosis or treatment decisions.