What is the formula for mean arterial pressure?

MAP = DBP + (1/3 × (SBP − DBP)), where the bracketed term is the pulse pressure. Equivalently, MAP = (SBP + 2 × DBP) / 3. The diastolic is weighted more heavily because the heart spends about two-thirds of the cardiac cycle in diastole.

What is a normal MAP?

A normal mean arterial pressure is roughly 70–100 mmHg. A MAP of at least 60–65 mmHg is generally needed to perfuse vital organs such as the brain, heart, and kidneys.

Why is 65 mmHg important?

A MAP of 65 mmHg is the common minimum target in critically ill and septic patients, below which organ perfusion is at risk. Sustained values under this threshold often trigger fluids or vasopressors.

Why weight the diastolic pressure?

MAP is the average pressure over a full cardiac cycle, not the simple midpoint. Because diastole lasts roughly twice as long as systole at normal heart rates, the diastolic pressure contributes about two-thirds of the average.

Is my data stored anywhere?

No. The calculation runs entirely in your browser and the blood-pressure values you enter are never transmitted to or saved on any server.

Mean Arterial Pressure (MAP) Calculator

The Mean Arterial Pressure (MAP) Calculator estimates the average pressure in a patient’s arteries during one cardiac cycle. Unlike the simple systolic and diastolic numbers, MAP is the single value that best reflects whether blood is reaching the organs, which is why it drives haemodynamic decisions in intensive care and the operating theatre.

How it works

MAP is not the midpoint of systolic and diastolic pressure. Because the heart spends about two-thirds of each cycle in diastole, the diastolic pressure is weighted more heavily:

MAP = DBP + ⅓ × (SBP − DBP)

which is algebraically the same as:

MAP = (SBP + 2 × DBP) ÷ 3

The term (SBP − DBP) is the pulse pressure. For a blood pressure of 120/80, MAP = 80 + (1/3)(120 − 80) = 80 + 13.3 ≈ 93 mmHg.

Interpretation and notes

A normal MAP is roughly 70–100 mmHg. A value of at least 60–65 mmHg is generally required to perfuse the brain, heart, and kidneys; the calculator flags any result below 65 mmHg as a perfusion concern. In sepsis and shock, a MAP target of 65 mmHg is a standard resuscitation goal, with fluids or vasopressors added when it cannot be met.

The estimate assumes a normal heart rate. At very high heart rates diastole shortens, so the one-third weighting becomes less exact; invasive arterial monitoring measures true MAP directly when precision matters.