Mean arterial pressure (MAP) is an average calculated blood pressure in an individual during a single cardiac cycle. Although methods of estimating MAP vary, a common calculation is to take one-third of the pulse pressure (the difference between the systolic and diastolic pressures), and add that amount to the diastolic pressure. A normal MAP is about 90 mmHg.

MAP is altered by cardiac output and systemic vascular resistance. It is used to estimate the risk of cardiovascular diseases, where a MAP of 90 mmHg or less is low risk, and a MAP of greater than 96 mmHg represents "stage one hypertension" with increased risk.

The mean arterial pressure is calculated as the sum of the diastolic blood pressure plus the difference of the systolic pressure to the diastolic pressure, with the difference divided by three, as shown in the equation below.

For example, a diastolic pressure of 70 mm Hg and a systolic pressure of 100 mm Hg would yield by means of the calculator below a MAP of 80 mm Hg.

Mean arterial pressure = diastolic blood pressure + ⁠(systolic blood pressure - diastolic blood pressure)/3⁠

Mean arterial pressure can be measured directly or estimated from systolic and diastolic blood pressure by using a formula.

In the direct approach, mean arterial pressure can be calculated exactly using an arterial catheter with a transducer; this device inserted into the bloodstream measures arterial pressure over time.

A less exact but less invasive approach is to use a blood pressure cuff or an oscillometric blood pressure device to determine systolic and diastolic blood pressure; these values can be plugged into a formula to estimate mean arterial pressure.