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Arterial Blood Gas Interpretation Calculator

Work out arterial blood gas interpretation instantly with clear inputs, formula shown and shareable results.

About Arterial Blood Gas Interpretation Calculator

Classifies the primary acid-base disorder from pH, PaCO2 and bicarbonate, then tests respiratory compensation against Winter's formula.

Formula

Winter's formula

Expected PaCO2 = 1.5 x HCO3 + 8 (plus or minus 2) for a simple metabolic acidosis

Worked example

With the default values below, Arterial Blood Gas Interpretation Calculator returns Primary disorder of Metabolic acidosis. Change any input above and every figure here is recalculated in your browser.

Inputs used

Arterial pHaccepts 6.6–7.8
7.3
PaCO2accepts 10–120 mmHg
30 mmHg
Bicarbonateaccepts 2–50 mmol/L
15 mmol/L

Results

Primary disorder
Metabolic acidosis
Expected PaCO2 by Winter's formula
30.5 mmHg
Compensation check
Appropriate respiratory compensation
pH status
Acidaemic

Step by step

  1. 1Values used
  2. 2Winter's formula
  3. 3Primary disorder= Metabolic acidosis
  4. 4Expected PaCO2 by Winter's formula= 30.5 mmHg
  5. 5Compensation check= Appropriate respiratory compensation
  6. 6pH status= Acidaemic

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
  • This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

What does a pH in range mean?

It can still hide a mixed disorder, so PaCO2 and bicarbonate are checked even when pH is normal.

Does this replace a full interpretation?

No. Anion gap, oxygenation, lactate and the clinical context are all needed for a complete reading.

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