Plasma Osmolality

Calculate Plasma Osmolality instantly with the exact formula and a worked example. Free online calculator — no signup, works on mobile.

Plasma Osmolality

Na
Glucose, mg/dL
BUN, mg/dL
Osm
290.5556mOsm/kg
Calculate Plasma Osmolality instantly with the exact formula and a worked example. Free online calculator — no signup, works on mobile.

More about: Plasma Osmolality

What it calculates

The “Plasma Osmolality” calculator computes Osm in mOsm/kg from 3 parameters: na, glucose, mg/dl, bun, mg/dl.

Used by professionals and patients to assess health metrics, dosages, and risks.

Example calculation

With parameters Na = 140, Glucose, mg/dL = 100, BUN, mg/dL = 14 the result is 290.56 mOsm/kg.

How to use

  1. Enter the parameter values — every field above is adjustable with a slider.
  2. The result and related metrics are calculated automatically as you type.
  3. Use the additional metrics shown (if any) where needed.
  4. Copy the result or bookmark the page.

Related calculators

FAQ

How is BMI calculated?
BMI = weight (kg) / height (m)². Example: 70 kg / (1.75 m)² = 22.9. The WHO normal range is 18.5–24.9; below that is underweight, 25–29.9 is overweight, and 30+ is obese.
Is BMI accurate for everyone?
No. BMI does not distinguish muscle from fat, so athletes may show a high BMI with low body fat. It is also less reliable for teenagers, pregnant people, older adults, and very tall or short individuals.
What are the BMI categories?
Underweight: below 18.5. Normal: 18.5–24.9. Overweight: 25–29.9. Obese class I: 30–34.9; class II: 35–39.9; class III: 40+.
What is a better measure than BMI?
Body fat percentage, waist-to-height ratio (aim for under 0.5), and waist circumference give a clearer picture of health than BMI alone.