Serum Osmolality Calculator

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

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About Serum Osmolality

  • • Normal: 275-295 mOsm/kg
  • • Formula: 2×Na + Glucose/18 + BUN/2.8
  • • High: Hyperosmolar states (dehydration, hyperglycemia)
  • • Low: Hyposmolar states (SIADH, overhydration)
  • • Used to assess fluid balance