Mean arterial pressure (MAP) calculator
Work out the mean arterial pressure from one systolic and diastolic reading with the standard formula, MAP = DBP + (SBP − DBP) ÷ 3, and see the pulse pressure and where the result sits against the 60, 65 and 70 mmHg reference points used in adult sepsis care.
Guides
- Normal MAP range: what is a good mean arterial pressure?What a normal mean arterial pressure is, why 65 mmHg is the septic shock target, and how MAP differs from systolic pressure, with worked readings.
How this mean arterial pressure calculator works
This mean arterial pressure calculator estimates the average pressure in the large arteries over one cardiac cycle from a single cuff or arterial line reading. It adds one-third of the pulse pressure to the diastolic pressure: MAP = DBP + (SBP − DBP) ÷ 3. Written another way, MAP = (SBP + 2 × DBP) ÷ 3, so diastolic pressure counts twice as much as systolic pressure. The weighting reflects a resting heart, in which diastole takes up about two-thirds of each beat. Razminia and colleagues describe the standard formula as weighted one-third systolic and two-thirds diastolic, with no correction for the larger share of each beat that systole takes as the heart rate rises. Pulse pressure, the difference between systolic and diastolic pressure, is shown too, because it is the step the formula divides by three. Both pressures must come from the same reading in mmHg, and the calculator checks that the systolic value is higher than the diastolic value before it gives a result.
MAP = DBP + (SBP − DBP) ÷ 3 = (SBP + 2 × DBP) ÷ 3
Pulse pressure = SBP − DBP. For 120/80 mmHg the pulse pressure is 40 mmHg and the MAP is 80 + 40 ÷ 3 = 93.3 mmHg; (120 + 160) ÷ 3 gives the same 93.3 mmHg.
The result is rounded to one decimal place, and the band is read from the value as shown, so 94/50 mmHg (MAP 64.7) sits below 65 while 95/50 mmHg (MAP exactly 65.0) meets it. The calculator accepts systolic pressures from 40 to 300 mmHg and diastolic pressures from 20 to 200 mmHg, and it asks you to check the reading if the systolic value is not the higher of the two.
MAP results: the 60, 65 and 70 mmHg reference points
A mean arterial pressure result is read against a few fixed reference points rather than a graded scale, because the 2025 AHA/ACC blood pressure guideline grades systolic and diastolic pressure and sets no MAP categories. The Surviving Sepsis Campaign 2021 guideline recommends an initial MAP target of 65 mmHg for adults with septic shock on vasopressors, a strong recommendation based on moderate-quality evidence, and its rationale notes that MAPs below a threshold of about 60 mmHg are associated with decreased organ perfusion. Sepsis-3 uses the same 65 mmHg line to define septic shock: a vasopressor requirement to keep MAP at 65 mmHg or more, plus a serum lactate above 2 mmol/L despite adequate fluid resuscitation. The SOFA score gives 1 cardiovascular point for a MAP below 70 mmHg. At the other end, any resting reading in the AHA/ACC normal category, below 120/80 mmHg, gives a MAP below 93.3 mmHg. From 70 mmHg up, the calculator also shows the reading's blood pressure category.
| MAP | What the source says |
|---|---|
| Below 60 mmHg | Surviving Sepsis Campaign 2021: MAPs below a threshold of about 60 mmHg are associated with decreased organ perfusion. |
| 60 to 64.9 mmHg | Under the initial MAP target of 65 mmHg recommended for adults with septic shock on vasopressors. |
| 65 to 69.9 mmHg | Meets the 65 mmHg target; a MAP below 70 mmHg scores 1 cardiovascular point in the SOFA score. |
| 70 mmHg or more | Above the sepsis and SOFA thresholds. The AHA/ACC category of the systolic and diastolic reading is shown. |
The 65 mmHg target comes mainly from SEPSISPAM, a 2014 trial of 776 patients with septic shock that compared MAP targets of 65 to 70 mmHg and 80 to 85 mmHg. Mortality at 28 days did not differ (34.0% against 36.6%), and atrial fibrillation was more frequent in the higher-target group. For what counts as a normal value outside sepsis, see the guide to the normal MAP range.
When the MAP formula is less accurate
The one-third mean arterial pressure formula approximates a value that a monitor can measure directly, and its error grows when the shape of the pressure wave changes. Heart rate is the main limit. As the heart beats faster, diastole shortens and systole fills a larger share of each cycle, so the true mean moves toward systolic pressure and a fixed one-third weighting underestimates it. Razminia and colleagues proposed a heart rate-corrected form, MAP = DBP + [0.33 + (heart rate × 0.0012)] × pulse pressure, and in 12 patients with a central aortic catheter, paced at rising heart rates, it matched computer-measured MAP more closely than the standard formula. Meaney and colleagues proposed 0.412 instead of 0.333 as the share of pulse pressure. In a 2016 study of 1,878 people, Papaioannou and colleagues found that MAP calculated with 0.412 correlated more strongly with left ventricular mass, aortic stiffness and carotid wall area than MAP from the traditional formula.
The fraction also differs along the arterial tree. Chemla and colleagues measured aortic pressure in 73 resting adults and found that the share of pulse pressure needed to reach the true aortic mean ranged from 0.35 to 0.53, averaging 0.45, and fell with age, MAP and wave reflection; the one-third rule is a brachial artery estimate. In shock, the cuff reading itself is the weak point: the Surviving Sepsis Campaign 2021 guideline states that non-invasive cuff estimates tend to be inaccurate, more so in shock states, and suggests invasive arterial pressure monitoring in septic shock as soon as practical where resources allow. The 60, 65 and 70 mmHg reference points apply to adults.
Questions
What is the formula for mean arterial pressure?
MAP = DBP + (SBP − DBP) ÷ 3, which is the same as (SBP + 2 × DBP) ÷ 3. For 120/80 mmHg both give 93.3 mmHg.
What is a normal MAP?
No guideline sets a normal MAP range. A resting reading in the AHA/ACC normal category, below 120/80 mmHg, gives a MAP below 93.3 mmHg. The guide to the normal MAP range works through common readings.
Why is 65 mmHg the MAP target in septic shock?
The Surviving Sepsis Campaign 2021 guideline recommends an initial target of 65 mmHg over higher targets for adults on vasopressors, because higher targets did not improve survival in trials such as SEPSISPAM and the 65 trial.
Is the formula accurate at a fast heart rate?
Less so. The one-third weighting assumes diastole fills about two-thirds of the cycle, which is true at rest. At faster rates it underestimates the true MAP; Razminia's heart rate-corrected formula was closer in paced patients.
Is my data sent anywhere?
No. The calculation runs in your browser, and the values you enter are not sent or stored.
Sources
- Evans L, Rhodes A, Alhazzani W, et al. Surviving Sepsis Campaign: international guidelines for management of sepsis and septic shock 2021. Intensive Care Med. 2021;47(11):1181–1247. doi:10.1007/s00134-021-06506-y. Also in Crit Care Med. 2021;49(11):e1063–e1143. doi:10.1097/CCM.0000000000005337
- Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801–810. doi:10.1001/jama.2016.0287
- Vincent JL, Moreno R, Takala J, et al. The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. Intensive Care Med. 1996;22(7):707–710. doi:10.1007/BF01709751
- Asfar P, Meziani F, Hamel JF, et al. High versus low blood-pressure target in patients with septic shock. N Engl J Med. 2014;370(17):1583–1593. doi:10.1056/NEJMoa1312173
- Lamontagne F, Richards-Belle A, Thomas K, et al. Effect of reduced exposure to vasopressors on 90-day mortality in older critically ill patients with vasodilatory hypotension: a randomized clinical trial. JAMA. 2020;323(10):938–949. doi:10.1001/jama.2020.0930
- 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
- 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
- Papaioannou TG, Protogerou AD, Vrachatis D, et al. Mean arterial pressure values calculated using seven different methods and their associations with target organ deterioration in a single-center study of 1878 individuals. Hypertens Res. 2016;39(9):640–647. doi:10.1038/hr.2016.41
- Chemla D, Hébert JL, Aptecar E, et al. Empirical estimates of mean aortic pressure: advantages, drawbacks and implications for pressure redundancy. Clin Sci (Lond). 2002;103(1):7–13. doi:10.1042/cs1030007
- Jones DW, Ferdinand KC, Taler SJ, et al. 2025 AHA/
ACC/ AANP/ AAPA/ ABC/ ACCP/ ACPM/ AGS/ AMA/ ASPC/ NMA/ PCNA/ SGIM guideline for the prevention, detection, evaluation and management of high blood pressure in adults. Hypertension. 2025;82(10):e212–e316. doi:10.1161/HYP.0000000000000249