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Mean Arterial Pressure (MAP) Calculator

Estimate mean arterial pressure from systolic and diastolic blood pressure.

Everyone & professionalsHeart & blood vesselsv1.0.1

Your measurements

mmHg
mmHg

Calculated on your device. Nothing is sent to a server.

Your result will appear here

Enter your measurements, then press Calculate.

Methodology

Standard MAP approximation

MAP = DBP + (SBP − DBP) ÷ 3

Because, at resting heart rates, diastole takes up roughly two-thirds of each beat, mean pressure is approximated as diastolic pressure plus one-third of the pulse pressure.

Who it is for
Adults and children (not newborns) with a measured blood pressure.
Version
1.0.1

How this calculator works

Where the formula comes from

  • Mean arterial pressure is the average pressure in the arteries over one cardiac cycle; it can be measured from an arterial waveform or estimated from systolic and diastolic pressure.[1]
  • The usual estimate, diastolic pressure plus one-third of the pulse pressure, approximates mean arterial pressure under typical resting conditions; its accuracy depends on heart rate and the shape of the arterial waveform.[2][3]

The inputs

  • The inputs are systolic and diastolic blood pressure in mmHg; pulse pressure is systolic minus diastolic, and the result is in mmHg.[1]

Versions and alternatives

  • A heart-rate-corrected version, diastolic + [0.33 + (heart rate × 0.0012)] × pulse pressure, agreed more closely with catheter-measured pressure in its validation study.[4]
  • In 57 people with intra-arterial brachial recordings, the true mean lay at about 40% of the pulse pressure above diastolic, and the one-third rule underestimated it by about 5 mmHg.[5]

Where accuracy falls (published evidence)

  • The one-third rule assumes a fairly stable relationship between the durations of systole and diastole; its accuracy can fall as heart rate and waveform change, including during exercise.[3][4]
  • In critically ill newborns, the relationship between mean and diastolic pressure differs from the adult one-third rule; one study found the mean at about 47% of the pulse pressure above diastolic.[6]

What guidelines say

  • The Surviving Sepsis Campaign 2021 guideline recommends an initial target mean arterial pressure of 65 mmHg in adults with septic shock receiving vasopressors.[7]

Sources

  1. DeMers D, Wachs D. Physiology, mean arterial pressure. StatPearls. Treasure Island (FL): StatPearls Publishing; 2023. PMID 30855814
  2. Meaney E, Alva F, Moguel R, Meaney A, Alva J, Webel R. Formula and nomogram for the sphygmomanometric calculation of the mean arterial pressure. Heart. 2000;84(1):64. doi:10.1136/heart.84.1.64
  3. Moran D, Epstein Y, Keren G, Laor A, Sherez J, Shapiro Y. Calculation of mean arterial pressure during exercise as a function of heart rate. Appl Human Sci. 1995;14(6):293–295. doi:10.2114/ahs.14.293
  4. Razminia M, Trivedi A, Molnar J, et al. Validation of a new formula for mean arterial pressure calculation: the new formula is superior to the standard formula. Catheter Cardiovasc Interv. 2004;63(4):419–425. doi:10.1002/ccd.20217
  5. Bos WJW, Verrij E, Vincent HH, Westerhof BE, Parati G, van Montfrans GA. How to assess mean blood pressure properly at the brachial artery level. J Hypertens. 2007;25(4):751–755. doi:10.1097/HJH.0b013e32803fb621
  6. Versmold HT, et al. Calculated mean arterial blood pressure in critically ill neonates. Basic Res Cardiol. 1993;88(1):80–85. doi:10.1007/BF00788533
  7. Evans L, Rhodes A, Alhazzani W, et al. Surviving Sepsis Campaign: international guidelines for management of sepsis and septic shock 2021. Crit Care Med. 2021;49(11):e1063–e1143. doi:10.1097/CCM.0000000000005337

Compiled from the published sources above. Every statement was agreed independently by three AI research tools (Claude, ChatGPT, DeepSeek) and its source verified in PubMed or Crossref by the Hakeemly editorial team. Not reviewed by a doctor unless stated. Agreed on

Worked example: how to calculate mean arterial pressure

Inputs

Systolic blood pressure (top number)
120 mmHg
Diastolic blood pressure (bottom number)
80 mmHg

Result

Mean arterial pressure
93 mmHg

Calculation:

80 + 40/3 = 93.33

An illustration with sample values, worked out with the same method the tool above uses.

Limitations

  • An approximation; less accurate at fast heart rates. Invasive monitoring measures MAP directly.

References

  1. DeMers D, Wachs D. Physiology, Mean Arterial Pressure. StatPearls. Treasure Island (FL): StatPearls Publishing; 2023. https://www.ncbi.nlm.nih.gov/books/NBK538226/

Continue with your measurements

Shared measurements carry over automatically, in this tab only.

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Systolic blood pressure (top number), Diastolic blood pressure (bottom number)

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The difference between systolic and diastolic blood pressure.

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Heart rate divided by systolic (SI) or mean arterial pressure (MSI).

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