Arterial Oxygen Content CalculatorFree online fitness & health calculator — instant results, no sign-up
Estimate arterial oxygen content from hemoglobin, saturation and oxygen pressure.
For general information only. This is not medical advice, diagnosis, dosing guidance or a treatment recommendation. Talk to a doctor or other qualified health professional about your health, pregnancy, or diet.
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About the Arterial Oxygen Content Calculator
The Arterial Oxygen Content Calculator estimates the amount of oxygen carried in arterial blood using hemoglobin concentration, arterial oxygen saturation, and arterial oxygen partial pressure. It combines oxygen bound to hemoglobin with oxygen dissolved in plasma and reports the total in mL O₂/dL. This adult educational estimate is not a diagnosis or treatment recommendation.
- Hemoglobin (g/dL)
- Hemoglobin is the concentration of the oxygen-carrying protein in blood, measured in grams per deciliter (g/dL), with a default of 14.
- Arterial oxygen saturation (%)
- Arterial oxygen saturation is the percentage of hemoglobin oxygen-binding sites occupied by oxygen, entered as a percentage with a default of 98.
- Arterial oxygen partial pressure (mmHg)
- Arterial oxygen partial pressure describes the pressure exerted by dissolved oxygen in arterial blood, measured in millimeters of mercury (mmHg), with a default of 95.
Formula and method
CaO₂ = (1.34 × Hb × SaO₂ / 100) + (0.0031 × PaO₂). With the default inputs: CaO₂ = (1.34 × 14 × 98 / 100) + (0.0031 × 95) = 18.6793 ≈ 18.68 mL O₂/dL.
- CaO₂Estimated arterial oxygen content, in mL O₂ per deciliter of blood.
- HbHemoglobin concentration, in g/dL.
- SaO₂Arterial oxygen saturation entered as a percentage; dividing by 100 converts it to a fraction.
- PaO₂Arterial oxygen partial pressure, in mmHg.
- 1.34Assumed oxygen-binding capacity of hemoglobin, in mL O₂ per gram of hemoglobin.
- 0.0031Approximate oxygen solubility coefficient in plasma at normal body temperature, in mL O₂/(dL·mmHg).
Convert saturation from percent to a fraction, then multiply it by hemoglobin and the oxygen-binding coefficient to estimate hemoglobin-bound oxygen. Multiply arterial oxygen partial pressure by the solubility coefficient to estimate dissolved oxygen. Add both contributions and round the total to two decimal places: the default inputs give 18.3844 + 0.2945 = 18.6793, displayed as 18.68 mL O₂/dL.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Hemoglobin14 g/dL
- Arterial oxygen saturation98 %
- Arterial oxygen partial pressure95 mmHg
Results
- Arterial oxygen content18.68 mL O₂/dL
- NoteEducational estimate for adults; not a diagnosis or treatment recommendation.
How to use the Arterial Oxygen Content Calculator
- 1Enter hemoglobin in g/dL; the default is 14.
- 2Enter arterial oxygen saturation as a percentage, not a decimal fraction; the default is 98.
- 3Enter arterial oxygen partial pressure in mmHg; the default is 95.
- 4Calculate the estimate and read the arterial oxygen content in mL O₂/dL.
- 5Review the educational note and interpret the result alongside clinical context rather than using it to make treatment decisions.
Reading your result
The 'Arterial oxygen content' row reports the estimated volume of oxygen in each deciliter of arterial blood. With hemoglobin 14 g/dL, saturation 98%, and arterial oxygen partial pressure 95 mmHg, it reads 18.68 mL O₂/dL. This is oxygen content, not oxygen saturation or the rate of oxygen delivery to tissues. The 'Note' row states: 'Educational estimate for adults; not a diagnosis or treatment recommendation.'
Limitations
The calculation assumes standard oxygen-binding and solubility coefficients and sufficiently accurate, contemporaneous arterial measurements. It does not directly account for abnormal hemoglobin species such as carboxyhemoglobin or methemoglobin, which can make a simple saturation-based estimate misleading. Pulse oximetry is not identical to measured arterial saturation, and venous oxygen pressure is not a substitute for PaO₂. Oxygen content alone cannot establish tissue oxygen delivery, which also depends on blood flow, or diagnose a medical condition. This tool is not a measure of fitness or a basis for changing oxygen therapy, supplements, or other treatment.
Common questions
Why does hemoglobin matter when arterial oxygen saturation is high?+
Saturation describes the proportion of available hemoglobin binding sites carrying oxygen, not how much hemoglobin is present. Less hemoglobin means less oxygen-carrying capacity even when saturation remains high.
Why include arterial oxygen partial pressure as well as saturation?+
Saturation estimates the oxygen bound to hemoglobin, while PaO₂ estimates the smaller dissolved-oxygen contribution. With the default inputs, these contributions are 18.3844 and 0.2945 mL O₂/dL, respectively.
Can I use a finger pulse oximeter reading for arterial oxygen saturation?+
A pulse oximeter provides SpO₂, an estimate rather than a direct measurement of SaO₂. Using it makes this calculation more approximate, especially with poor circulation, motion, or abnormal hemoglobin species; it also does not provide PaO₂.
Does the default result of 18.68 mL O₂/dL prove that tissues are receiving enough oxygen?+
No. It estimates arterial oxygen content only. Tissue oxygen delivery also depends on cardiac output and regional blood flow, while adequacy depends on tissue oxygen demand and extraction.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.