Plasma Osmolality Calculator

2×Na + glucose/18 + BUN/2.8.

Osmolality (mOsm/kg) 290

Step-by-step with your numbers:

1. Values used:

2. Sodium = 140 mmol/L

3. Glucose = 90 mg/dL

4. BUN = 14 mg/dL

5. Osmolality = 290mOsm/kg

Did we solve your problem today?

Calculated plasma osmolality. Normal ~275–295. Informational only.

FAQ

Measured vs calc?

The osmolar gap = measured − calculated (normally <10).