What is Mean Arterial Pressure (MAP)?

Mean Arterial Pressure is the average arterial pressure throughout one cardiac cycle. Because the heart spends roughly two-thirds of each cycle in diastole (relaxation) and only one-third in systole (contraction), MAP is not simply the midpoint between SBP and DBP — it is weighted toward diastolic pressure. The standard clinical formula is MAP = (2 x DBP + SBP) / 3, which is equivalent to MAP = DBP + (SBP - DBP) / 3.

What is a normal MAP range for adults?

A MAP between 70 and 100 mmHg is generally considered normal for a healthy resting adult. A MAP below 65 mmHg is the widely-used clinical threshold for inadequate organ perfusion (used in sepsis and shock protocols). A MAP consistently above 110 mmHg indicates hypertension. These are population-level reference values; individual targets vary by condition and are determined by a clinician.

Why does the MAP formula weight diastolic pressure twice?

At a typical resting heart rate of 60-80 bpm, each cardiac cycle lasts about 0.8-1 second. Systole (the ejection phase) occupies roughly one-third of that time, while diastole occupies the remaining two-thirds. Arterial pressure therefore spends proportionally more time near the diastolic value, so MAP = (1 x SBP + 2 x DBP) / 3. At higher heart rates diastole shortens and MAP shifts closer to the simple arithmetic mean, but the (2 x DBP + SBP) / 3 formula remains the standard clinical approximation.

What is pulse pressure and why does it matter?

Pulse pressure (PP) is the difference between systolic and diastolic pressure. A normal resting PP is roughly 40 mmHg (e.g. 120 - 80). A widened PP (above 60 mmHg) may indicate aortic regurgitation, atherosclerosis, or high stroke volume. A narrowed PP (below 25 mmHg) may suggest hypovolaemia, aortic stenosis, or cardiac tamponade. This calculator displays PP alongside MAP so you can assess both values together.

Is MAP the same as average blood pressure?

MAP is a time-weighted average, not a simple arithmetic average. The arithmetic mean of SBP and DBP (midpoint) is (SBP + DBP) / 2, whereas MAP = (SBP + 2 x DBP) / 3. For a reading of 120/80 mmHg the arithmetic mean is 100 mmHg but the MAP is (120 + 160) / 3 = 93.3 mmHg. In clinical practice, MAP is preferred because it better reflects the perfusion pressure driving blood to organs.

Is this calculator medically certified?

No. This tool is for educational and informational use only. It implements the standard MAP formula used in clinical literature, but it cannot account for individual patient conditions, measurement technique, or any clinical context. Always consult a qualified healthcare professional for interpretation of blood pressure readings and treatment decisions.

MAP Calculator (Mean Arterial Pressure)

Mean Arterial Pressure (MAP) is one of the most important haemodynamic parameters in clinical medicine. It represents the average pressure in the arteries during a full cardiac cycle — not simply the midpoint between your systolic and diastolic readings. Because the heart rests (diastole) for about twice as long as it contracts (systole), the MAP formula weights the diastolic value more heavily. Clinicians use MAP to assess whether tissues are receiving enough blood flow, to guide vasopressor dosing in intensive care, and to monitor patients during surgery. A MAP below 65 mmHg is a widely recognised danger threshold — below this level, vital organs such as the kidneys, brain, and liver may not receive adequate perfusion.

This calculator implements the standard formula used in hospitals and emergency settings worldwide:

MAP = (2 x DBP + SBP) / 3

where SBP is your systolic (top) blood pressure and DBP is your diastolic (bottom) blood pressure, both in millimetres of mercury (mmHg). An algebraically identical form is MAP = DBP + (SBP - DBP) / 3, which makes it clear that MAP equals the diastolic pressure plus one-third of the pulse pressure. Both forms are shown in the results so you can verify the working.

How it works

The formula comes from a simple time-weighted model of the cardiac cycle. At a resting heart rate of roughly 70 bpm, each beat lasts about 0.85 seconds. Systole (the ejection phase, when the ventricle pumps blood out) lasts approximately 0.3 seconds — about one-third of the cycle. Diastole (the filling phase) occupies the remaining two-thirds. Pressure during systole is high (SBP) and pressure during diastole is lower (DBP), so the time-averaged pressure is:

MAP = (1/3) x SBP + (2/3) x DBP = (SBP + 2 x DBP) / 3

This is mathematically the same as (2 x DBP + SBP) / 3.

The calculator also computes pulse pressure (PP = SBP - DBP), a secondary measure used to screen for arterial stiffness, valve disease, and volume status. A normal resting PP is approximately 40 mmHg; values persistently above 60 mmHg or below 25 mmHg warrant clinical review.

Worked example

Consider a reading of 130/85 mmHg (a common “high-normal” blood pressure):

SBP = 130 mmHg, DBP = 85 mmHg
MAP = (2 x 85 + 130) / 3 = (170 + 130) / 3 = 300 / 3 = 100 mmHg
Pulse pressure = 130 - 85 = 45 mmHg

At 100 mmHg the MAP sits at the upper edge of the normal range (70-100 mmHg). Now compare a reading of 90/60 mmHg (borderline low):

MAP = (2 x 60 + 90) / 3 = (120 + 90) / 3 = 210 / 3 = 70 mmHg
This is at the lower end of normal; a further drop to 80/50 mmHg would give MAP = (2 x 50 + 80) / 3 = 60 mmHg — below the critical 65 mmHg threshold.

SBP (mmHg)	DBP (mmHg)	MAP (mmHg)	Classification
120	80	93.3	Normal
130	85	100.0	Normal (upper)
100	65	76.7	Normal (lower)
90	60	70.0	Normal (lower limit)
80	50	60.0	Below normal
70	40	50.0	Critical
150	100	116.7	Hypertensive

Every calculation runs entirely in your browser — no blood pressure values are uploaded or stored anywhere.