Oxygen Content Calculator

Determines arterial oxygen based on haemoglobin, O2 saturation and arterial pressure.

You can read more about the variables and the formula used in the text below the form.

The oxygen content calculator uses the haemoglobin levels in g/dL, the percentage of oxygen saturation and O2 arterial pressure in mmHg, to determine the arteria oxygen content.

Arterial Oxygen Content = Hemoglobin x 1.36 x SaO2 /100 + 0.0031 x PaO2

Oxygen saturation
Arterial oxygen pressure
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Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.


Variables and formula

Arterial blood oxygen is the measure of the oxygen in 100 ml of blood both bound or unbound by hemoglobin.

It offers information about the uncombined part of oxygen which can become of interest at high values of PaO2 or in patients diagnosed or suspected of anemia.

The three variables used are described in the table below:

Variable Normal values Description
Hemoglobin 13.8 - 17.2 g/dL for men
12.1 - 15.1 g/dL for women
Complex protein on the RBCs, involved in oxygen transport
SaO2 Between 95 and 100%. Arterial blood-oxygen saturation, determined during pulse oximetry
PaO2 75 and 100 mmHg Arterial pressure of oxygen

The following formula is employed:

Arterial Oxygen Content = Hemoglobin x 1.36 x SaO2 / 100 + 0.0031 x PaO2

This can be explained as: CaO2 is the amount of oxygen bound to hemoglobin (1.36 x Hb x SaO2) plus the oxygen dissolved in plasma (0.0031 x PaO2).

The 1.36 constant represents the amount of oxygen (ml at 1 atmosphere) bound per gram of hemoglobin.

In some cases, the 1.36 constant is reduced to 1.34 because of abnormal forms of hemoglobin such as carboxyhemoglobin and methemoglobin.

The dissolved oxygen constant (0.0031) becomes of relevance at very high PaO2 (as in a hyperbaric chamber) or in severe anemia.



1. Anthea M, Hopkins J, McLaughlin CW, Johnson S, Warner MQ, LaHart D, Wright JD. Human Biology and Health. Englewood Cliffs NJ: Prentice Hall, 1993.

2. Stoelting RK, Pharmacology & Physiology in Anesthetic Practice, Lippincott Williams & Wilkins, 1999.

3. Hsia CC. Respiratory function of hemoglobin. N Engl J Med. 1998; 338(4):239-47.

Specialty: Pulmonology

System: Respiratory

Objective: Determination

Type: Calculator

No. Of Variables: 3

Article By: Denise Nedea

Published On: June 7, 2017

Last Checked: June 7, 2017

Next Review: June 7, 2023