Last updated: 2026-06-21

Mean Arterial Pressure

Mean arterial pressure (MAP) is the average pressure in a person's arteries during one cardiac cycle. It is a better single indicator of organ perfusion than systolic pressure alone, because it represents the steady force that drives blood to the brain, kidneys, and other tissues. This calculator estimates it from an ordinary blood-pressure reading.

How it is defined

The bedside estimate is:

$\mathrm{MAP} = \mathrm{DBP} + \dfrac{\mathrm{SBP} - \mathrm{DBP}}{3}$

where SBP is the systolic pressure and DBP the diastolic pressure. The gap between the two, $\mathrm{SBP} - \mathrm{DBP}$, is the pulse pressure; only one-third of it is added to the diastolic value. This weighting exists because at a resting heart rate the heart spends roughly twice as long relaxing (diastole) as contracting (systole), so the average pressure lies closer to the diastolic reading.

Worked example

For a typical reading of 120/80 mmHg:

A mean arterial pressure of about 93 mmHg sits comfortably in the normal range of roughly 70 to 100 mmHg.

Interpretation and limits

A mean arterial pressure of at least 60 mmHg is generally regarded as the minimum needed to perfuse the vital organs, while sustained values above 100 mmHg suggest elevated pressure. The one-third formula assumes a resting heart rate; when the heart beats quickly the diastolic phase shortens and the estimate drifts from the true average. For the underlying reading and its category, see the Blood Pressure Classifier, and for the related pulse measure the Pulse Pressure Calculator.