Blood pressure · Hemodynamics
Mean arterial pressure calculator.
Enter a systolic and a diastolic reading to get the mean arterial pressure and the pulse pressure, using the standard one-third, two-thirds estimate.
A reading of 120/80 mmHg gives a mean arterial pressure of 93.3 mmHg and a pulse pressure of 40 mmHg. A reading of 90/50 mmHg gives a MAP of 63.3 mmHg, below the 70 to 100 range.
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How mean arterial pressure is calculated
MAP = (systolic + 2 × diastolic) / 3, which is the same as diastolic + one third of the pulse pressure. The Tien paper listed under Sources calls this "Gauer's method (DP + 1/3*PP)", devised in 1960, and describes it as the most commonly used standard estimate. The two ways of writing it are algebraically identical: diastolic + (systolic - diastolic) / 3 simplifies to (systolic + 2 × diastolic) / 3. The weighting reflects the fact that the heart spends longer in diastole than in systole at a resting heart rate, so diastolic pressure counts for more of the cycle.
The same paper states that the normal range of MAP in humans is generally understood to be between 70 and 100 mmHg, and that is the band this calculator compares your result to. It also notes that earlier formulas were thought to be inaccurate at higher heart rates, and that other weightings exist, such as 0.42 systolic + 0.58 diastolic (Wezler) and diastolic + 0.412 × pulse pressure (Meaney). Their own validation used pig femoral artery pressures, and they say the findings for peripheral arteries in humans still need confirmation, so treat any cuff-based MAP as an approximation.
Worked example
For 120/80 mmHg: pulse pressure is 120 - 80 = 40. One third of 40 is 13.3, and 80 + 13.3 = 93.3 mmHg. Using the other form, (120 + 2 × 80) / 3 = 280 / 3 = 93.3, the same. For 90/50: pulse pressure 40, one third 13.3, MAP 63.3. Notice that a plain average of 120 and 80 would give 100, which overstates MAP by almost 7 mmHg; the result panel shows that plain average only so you can see the difference.
Pulse pressure, shown in the result, is simply systolic minus diastolic. This page does not grade it, because the sources checked for this update did not agree on a single published cut-off for a wide pulse pressure that could be quoted here. If a number matters for a decision, it should be read by your clinician against your own baseline, not against a generic band.
Common mix-ups
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Often assumedMean arterial pressure is just the average of the systolic and diastolic numbers.
What the source saysThe standard estimate described in the paper is diastolic plus one third of the pulse pressure, devised by Gauer in 1960. For 120/80 that is 93.3 mmHg, not the plain average of 100. [1]
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Often assumedThe one-third rule is exact at any heart rate.
What the source saysThe authors note that earlier formulas were thought to be inaccurate at higher heart rates, and that their own pig data came from femoral arteries, so the human peripheral result still needs validation. [1]
Checked against these sources on .
Frequently asked questions
What is the formula for mean arterial pressure?
MAP = (systolic + 2 x diastolic) / 3, equivalent to diastolic + one third of the pulse pressure. A 120/80 reading gives 93.3 mmHg.
What is a normal MAP?
A Tien and colleagues 2023 paper in the American Journal of Hypertension states the normal range in humans is generally understood to be 70 to 100 mmHg. Whether a particular value is acceptable for a particular patient is a clinical judgment.
Why is diastolic pressure counted twice?
The one-third, two-thirds weighting reflects that the cardiac cycle spends more time in diastole than systole at a resting heart rate. It is an approximation, and it is thought to be less accurate at higher heart rates.
Is MAP the average of the systolic and diastolic numbers?
No. A plain average of 120 and 80 is 100, while the standard MAP estimate for the same reading is 93.3. The calculator shows both so you can see the gap.
Is a cuff-based MAP as good as an arterial line?
No. The formula estimates the mean from two points on the pressure wave. Invasive monitoring measures the whole waveform, and the formula is only an approximation of that mean.
Sources
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Not medical advice
This calculator does arithmetic on the numbers you type and does not diagnose or treat anything. Results depend on the quality of the inputs and the equation used. Lab values, drug doses and ECG readings must be interpreted by a clinician who knows the patient; contact your care team or emergency services for anything urgent.