By Zencalcy Editorial TeamLast reviewed About us
Oxygen delivery is the amount of oxygen the circulation transports to the tissues each minute. It is the product of cardiac output and arterial oxygen content, with a factor of ten to reconcile the units. This calculator returns the estimate in millilitres per minute and compares it with the commonly cited resting value.
Estimated oxygen reaching the tissues each minute.
DO2 = CO × CaO2 × 10
Cardiac output is in litres per minute and arterial oxygen content is in mL O2 per dL, so the factor of ten converts decilitres to litres. A resting value around 1,000 mL/min is commonly cited, though it varies with body size and metabolic demand. Delivery is only half of the picture; oxygen consumption and extraction also determine whether tissues are adequately supplied.
| Symbol | Meaning |
|---|---|
| CO | Cardiac output in litres per minute. |
| CaO2 | Arterial oxygen content in mL O2 per dL. |
| DO2 | Oxygen delivery in millilitres per minute. |
DO2 = 5 × 20 × 10 = 1,000 mL/min, matching the commonly cited resting value. With CO 4 L/min and CaO2 18 mL/dL, DO2 = 4 × 18 × 10 = 720 mL/min. A higher output or a higher oxygen content raises delivery, which is why both variables appear in the formula.
Oxygen delivery describes the conveyor belt, not the destination. The body normally delivers far more oxygen than it consumes, leaving a reserve that can be drawn on during illness or exertion. When delivery falls, tissues can increase extraction for a time, which is why a moderate drop may not immediately cause harm. The margin narrows when cardiac output falls, when haemoglobin is low or when saturation drops. Measuring delivery helps make those contributors explicit, but it does not measure whether the balance has tipped. That requires markers of tissue metabolism and perfusion. The formula is also a reminder that oxygen content, not saturation alone, drives transport: a patient with a normal saturation but severe anaemia can still have low delivery.
Continue with the Mean Arterial Pressure Calculator, Pulse Pressure Calculator, or the QTc Calculator — or browse more cardiology tools and all health calculators.
Around 1,000 mL/min is commonly quoted for resting adults, but the value scales with body size and metabolic rate. It is a reference point rather than a universal target, and trends are often more informative than a single measurement.
Blood pressure, ECG and risk scores are screening aids, not diagnoses. A single reading can be misleading; trends and proper technique matter. Scores estimate population risk and do not replace clinical assessment, anticoagulation decisions or emergency care.
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Last reviewed: September 2026. See how we build and check every tool on the about page.
Content updated: September 2026