Mean Arterial Pressure Calculator
The average pressure driving perfusion.
Mean Arterial Pressure Calculator
MAP = diastolic + (systolic - diastolic) / 3.
Calculated instantly
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What This Calculator Does
The Mean Arterial Pressure Calculator converts a systolic and diastolic reading into mean arterial pressure and pulse pressure. MAP approximates the average pressure in the arteries during one cardiac cycle and is used in critical care to judge organ perfusion.
How It Works
MAP is estimated as diastolic pressure plus one third of the difference between systolic and diastolic. The weighting reflects the fact that the heart spends about twice as long in diastole as in systole at a normal rate. Pulse pressure is the simple systolic minus diastolic difference, and the diastolic share shows how much of the mean comes from the resting phase.
Example
A reading of 120 over 80 gives a pulse pressure of 40 and a MAP of 80 + 40/3 = 93.3 mmHg. The diastolic share is 80 / 93.3 = 85.7 percent.
Formula
diastolic + (systolic - diastolic) / 3systolic - diastolicdiastolic / MAPReading the Results
Mean arterial pressure
An estimate of average arterial pressure. It is not a replacement for a monitored arterial line in unstable patients.
Pulse pressure
The gap between systolic and diastolic. It reflects stroke volume and arterial compliance and changes with age and disease.
Diastolic share of MAP
How much of the mean comes from diastole. It is a quick check that the one-third approximation is behaving as expected.
Sources and References
American Heart Association - Blood pressure measurement
Systolic and diastolic pressure
Guidance on measuring blood pressure accurately and interpreting the two numbers.
Surviving Sepsis Campaign - Hemodynamic Support
MAP target in septic shock
Recommends an initial MAP target of 65 mmHg, individualised to the patient.
References identify the method or data behind this calculator. Where a standard or tariff changes, the current edition applies, and the assumptions stated above take precedence over a remembered figure.
Frequently Asked Questions
What is a normal mean arterial pressure?
A resting MAP is commonly around 70-100 mmHg, but the normal range depends on age, activity, and clinical context. In critical care, 65 mmHg is a common lower target for organ perfusion. A single number does not define health or illness.
Why is diastolic weighted more than systolic?
The cardiac cycle spends roughly twice as long in diastole as in systole at a normal heart rate, so the mean is closer to diastolic. The one-third formula is an approximation; at fast or irregular heart rates the true mean can differ.
Is MAP the same as blood pressure?
No. Blood pressure is reported as two numbers, systolic and diastolic. MAP collapses them into an average pressure over the cycle. It is useful for perfusion assessment but does not replace either number or a full clinical evaluation.
What does a wide pulse pressure mean?
A wide gap can reflect arterial stiffness, a high stroke volume, or conditions such as aortic regurgitation. It is not diagnostic on its own. Age, medications, and other findings matter, so discuss a persistent change with a clinician.
Can I use this for exercise or altitude planning?
It is arithmetic, not a fitness or altitude model. Exercise and altitude change cardiac output and vascular resistance in ways the formula does not capture. Use it to understand a reading, not to set a training or acclimatisation target.