Osmolality Calculator

Calculate serum osmolality accurately with our advanced tool, designed for health professionals and nutrition experts.

Osmolality Calculator

Full original guide (expanded)

Calculate Serum Osmolality

Enter the required values to calculate serum osmolality.

Results

Calculated Osmolality: --

Data Source and Methodology

All calculations are based rigorously on the formulas and data provided by the authoritative source: MDCalc.

The Formula Explained

The serum osmolality is calculated using the formula:

Osmolality (mOsm/kg) = 2 × [Na+] + [Glucose]/18 + [BUN]/2.8

Glossary of Terms

  • [Na+]: Sodium concentration in mmol/L.
  • [Glucose]: Glucose concentration in mg/dL.
  • [BUN]: Blood Urea Nitrogen concentration in mg/dL.

How It Works: A Step-by-Step Example

Suppose a patient has [Na+] = 140 mmol/L, [Glucose] = 90 mg/dL, and [BUN] = 14 mg/dL. The osmolality would be calculated as:

Osmolality = 2 × 140 + 90/18 + 14/2.8 = 280 + 5 + 5 = 290 mOsm/kg

Frequently Asked Questions (FAQ)

What is serum osmolality?

Serum osmolality is a measure of the solute concentration in blood.

Why is osmolality important?

Osmolality helps assess the body's water-electrolyte balance.

How frequently should osmolality be checked?

It depends on clinical circumstances, often checked in cases of dehydration or electrolyte imbalance.

What affects serum osmolality?

Factors include sodium, glucose, and urea levels.

Can I calculate osmolality manually?

Yes, using the formula provided above.


Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted text)
Osmolality (mOsm/kg) = 2 × [Na+] + [Glucose]/18 + [BUN]/2.8
Formula (extracted text)
Osmolality = 2 × 140 + 90/18 + 14/2.8 = 280 + 5 + 5 = 290 mOsm/kg
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn

Osmolality Calculator

Calculate Serum Osmolality

Enter the required values to calculate serum osmolality.

Results

Calculated Osmolality: --

Data Source and Methodology

All calculations are based rigorously on the formulas and data provided by the authoritative source: MDCalc.

The Formula Explained

The serum osmolality is calculated using the formula:

Osmolality (mOsm/kg) = 2 × [Na+] + [Glucose]/18 + [BUN]/2.8

Glossary of Terms

  • [Na+]: Sodium concentration in mmol/L.
  • [Glucose]: Glucose concentration in mg/dL.
  • [BUN]: Blood Urea Nitrogen concentration in mg/dL.

How It Works: A Step-by-Step Example

Suppose a patient has [Na+] = 140 mmol/L, [Glucose] = 90 mg/dL, and [BUN] = 14 mg/dL. The osmolality would be calculated as:

Osmolality = 2 × 140 + 90/18 + 14/2.8 = 280 + 5 + 5 = 290 mOsm/kg

Frequently Asked Questions (FAQ)

What is serum osmolality?

Serum osmolality is a measure of the solute concentration in blood.

Why is osmolality important?

Osmolality helps assess the body's water-electrolyte balance.

How frequently should osmolality be checked?

It depends on clinical circumstances, often checked in cases of dehydration or electrolyte imbalance.

What affects serum osmolality?

Factors include sodium, glucose, and urea levels.

Can I calculate osmolality manually?

Yes, using the formula provided above.


Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted text)
Osmolality (mOsm/kg) = 2 × [Na+] + [Glucose]/18 + [BUN]/2.8
Formula (extracted text)
Osmolality = 2 × 140 + 90/18 + 14/2.8 = 280 + 5 + 5 = 290 mOsm/kg
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn

Osmolality Calculator

Calculate Serum Osmolality

Enter the required values to calculate serum osmolality.

Results

Calculated Osmolality: --

Data Source and Methodology

All calculations are based rigorously on the formulas and data provided by the authoritative source: MDCalc.

The Formula Explained

The serum osmolality is calculated using the formula:

Osmolality (mOsm/kg) = 2 × [Na+] + [Glucose]/18 + [BUN]/2.8

Glossary of Terms

  • [Na+]: Sodium concentration in mmol/L.
  • [Glucose]: Glucose concentration in mg/dL.
  • [BUN]: Blood Urea Nitrogen concentration in mg/dL.

How It Works: A Step-by-Step Example

Suppose a patient has [Na+] = 140 mmol/L, [Glucose] = 90 mg/dL, and [BUN] = 14 mg/dL. The osmolality would be calculated as:

Osmolality = 2 × 140 + 90/18 + 14/2.8 = 280 + 5 + 5 = 290 mOsm/kg

Frequently Asked Questions (FAQ)

What is serum osmolality?

Serum osmolality is a measure of the solute concentration in blood.

Why is osmolality important?

Osmolality helps assess the body's water-electrolyte balance.

How frequently should osmolality be checked?

It depends on clinical circumstances, often checked in cases of dehydration or electrolyte imbalance.

What affects serum osmolality?

Factors include sodium, glucose, and urea levels.

Can I calculate osmolality manually?

Yes, using the formula provided above.


Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted text)
Osmolality (mOsm/kg) = 2 × [Na+] + [Glucose]/18 + [BUN]/2.8
Formula (extracted text)
Osmolality = 2 × 140 + 90/18 + 14/2.8 = 280 + 5 + 5 = 290 mOsm/kg
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn
Formulas

(Formulas preserved from original page content, if present.)

Citations

(Citations preserved from original page content, if present.)

Changelog
  • 0.1.0-draft — (auto-wrapped): Canonical shell enforced without modifying calculator logic.
Version 0.1.0-draft