Mean Arterial Pressure (MAP) Calculator
Estimate conventional mean arterial pressure from one systolic and diastolic blood-pressure reading using the one-third pulse-pressure formula.
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About
This calculator estimates mean arterial pressure (MAP) from a paired systolic blood pressure (SBP) and diastolic blood pressure (DBP) reading in mmHg. MAP is the average pressure over one cardiac cycle, but this page returns only the conventional one-third pulse-pressure arithmetic estimate; it does not integrate an arterial pressure waveform; it is not the time integral of an arterial waveform and does not reproduce a monitor's proprietary algorithm. [1]
The estimate is only as reliable as the source reading. Cuff size, posture, rest, talking, movement, device validation, measurement site, arrhythmia, and repeated-reading technique can change SBP and DBP before any formula is applied. The page does not correct those errors or prove adequate brain, kidney, coronary, or other organ perfusion. [2, 3]
A MAP number does not diagnose shock or hypertension and is not a prescription for fluids, vasopressors, transfusion, monitoring, or another treatment. The static sepsis guideline context below is population-specific and never dynamically compared with a submitted result. [7, 8, 9]
Formula
Interpretation
What the estimate represents
The number is the conventional arithmetic estimate of average arterial pressure from one systolic/diastolic pair. SBP is the peak pressure and DBP is the lower pressure between beats; pulse pressure is SBP minus DBP. The estimate cannot prove whether blood flow to a particular organ is adequate and cannot replace symptoms, examination, repeated measurements, waveform, laboratory information, or an applicable clinical pathway. [1]
How to enter the measurement
Copy SBP and DBP from the same clinically obtained blood-pressure reading in mmHg. Do not pair the systolic value from one time, arm, device, or body position with a diastolic value from another. Cuff fit, rest, movement, talking, measurement site, device validation, arrhythmia, and repeated-reading technique can all change the source values; this calculator cannot detect or repair those conditions. [2, 3]
Worked arithmetic example
For 120/80 mmHg, pulse pressure is 40 mmHg and the conventional estimate is 80 + (120 − 80) ÷ 3 = 93.333... mmHg, displayed as 93.3 mmHg. This is an arithmetic example, not a normal-value example; displayed rounding is not fed back into the calculation.
Estimated MAP is not measured MAP
Three related values should not be treated as interchangeable: this page's fixed formula estimate, a waveform-integrated MAP obtained by averaging pressure over time across a cardiac cycle, and a device-reported MAP produced by a monitor's own signal processing. Published comparisons found that the one-third rule can underestimate brachial waveform MAP on average, with individual and activity-related differences. [4, 5]
Static 2026 septic-shock guideline context
| Guideline population | Published initial target context |
|---|---|
| Adults with septic shock | The 2026 Surviving Sepsis Campaign recommends an initial MAP target of 65 mmHg over higher targets for adults with septic shock; certainty of evidence is moderate. |
| Adults with septic shock age 65 years or older | The guideline suggests an initial range of 60–65 mmHg over higher ranges for adults with septic shock aged 65 years or older; certainty of evidence is low. |
This is fixed, population-specific guideline context, not a universal healthy range and not a comparison with the submitted result. The 65 Trial and SEPSISPAM studied selected critically ill populations and targets; their findings do not create a target for ordinary cuff readings. The page does not know whether sepsis or shock is present, whether vasoactive support is used, whether an arterial line is indicated, or what target is appropriate. [7, 8, 9]
Scope and limitations
There is no universal MAP target that applies to every adult, child, pregnancy, surgery, neurologic condition, trauma, hemorrhage, chronic hypertension, mechanical circulatory support, or critical illness. Pediatric and pregnancy interpretation is age-, gestation-, and context-specific. Direct arterial monitoring, device-reported values, and specialty protocols may use different measurement methods or targets. Use the estimate only as transparent arithmetic alongside the original reading and relevant clinical context. [2, 7]
Formula estimate, waveform MAP, and device MAP
| Concept | How it is obtained | What this page does |
|---|---|---|
| Traditional formula estimate | DBP + one third of SBP − DBP from one paired reading. | Calculates this one neutral estimate. |
| Waveform-integrated MAP | Pressure–time integration across a cardiac cycle. | Does not collect or integrate a waveform. |
| Device-reported MAP | Monitor-specific signal processing and measurement method. | Cannot identify or reproduce a device algorithm. |
These concepts can differ and should not be treated as interchangeable. [1, 4, 5]
Measurement quality and paired readings
Use SBP and DBP from the same reading, both in mmHg. Do not mix different times, arms, devices, sites, cuff sizes, postures, activity states, or unknown timing. AHA measurement guidance emphasizes validated and calibrated devices, appropriate cuff size, rest, position, no talking or movement, and repeated readings when a clinical measurement is needed. Cuff studies show variable agreement with intra-arterial references; no fixed correction can be applied to an individual input. [2, 3]
Why the one-third coefficient remains a fixed choice here
Bos 2007 found that the traditional rule underestimated brachial waveform MAP on average and studied a 0.40 coefficient. Grillo 2020 compared several fixed formulas with brachial pulse-wave analysis, while Kaypakli 2021 evaluated a heart-rate and pulse-pressure-adjusted model. These are different research models; group-level mean differences are not a personal correction factor. This page does not rank, switch, or combine them. [4, 5, 6]
What the number cannot determine
A formula estimate cannot establish adequate brain, kidney, coronary, or other organ perfusion; normal cardiac output or blood volume; absence of shock; presence or absence of hypertension; or a need for fluids, vasopressors, transfusion, monitoring, or other treatment. Organ blood flow also depends on cardiac output, vascular resistance, local autoregulation, baseline pressure, illness, trends, and response to care. The page makes none of those determinations.
Static sepsis evidence, not a calculator target
The 2026 SSC adult guideline recommends an initial 65 mmHg MAP target over higher targets for adults with septic shock (moderate certainty), and suggests 60–65 mmHg over higher ranges for adults with septic shock aged 65 years or older (low certainty). Its implementation remark notes that exactly 65 mmHg is not feasible to maintain and gives a practical range around that target. These statements apply only to the specified septic-shock populations. SEPSISPAM compared higher and lower targets in septic shock, and the 65 Trial studied permissive hypotension in older ICU patients with vasodilatory hypotension; neither trial creates a general target for a home cuff number or this page's result. [7, 8, 9]
The page does not know whether sepsis, shock, vasopressor use, arterial-line monitoring, chronic hypertension, trauma, hemorrhage, neurocritical illness, pregnancy, surgery, pediatric age, or mechanical circulatory support is present. It therefore never labels a submitted value as below, within, or above a guideline target.
Technical input boundaries
The ordinary-decimal parser, positive-input rules, display limits, and one-decimal formatting are software safeguards. They are not healthy ranges, diagnostic cutoffs, or treatment thresholds. SBP equal to DBP is retained as transparent arithmetic with zero pulse pressure; SBP below DBP is rejected because that pair fails the page's pressure relationship contract.
References
- DeMers D, Wachs D. Physiology, Mean Arterial Pressure. StatPearls [Internet]. StatPearls Publishing; updated 2026. PMID 30855814. Bookshelf ID NBK538226.
- Muntner P, Shimbo D, Carey RM, et al. Measurement of Blood Pressure in Humans: A Scientific Statement From the American Heart Association. Hypertension. 2019;73(5):e35–e66. PMID 30827125. PMCID PMC11409525. DOI 10.1161/HYP.0000000000000087.
- Picone DS, Schultz MG, Otahal P, et al. Accuracy of Cuff-Measured Blood Pressure: Systematic Reviews and Meta-Analyses. J Am Coll Cardiol. 2017;70(5):572–586. PMID 28750701. DOI 10.1016/j.jacc.2017.05.064.
- Bos WJW, Verrij E, Vincent HH, et al. How to assess mean blood pressure properly at the brachial artery level. J Hypertens. 2007;25(4):751–755. PMID 17351365. DOI 10.1097/HJH.0b013e32803fb621.
- Grillo A, Salvi P, Furlanis G, et al. Mean arterial pressure estimated by brachial pulse wave analysis and comparison with currently used algorithms. J Hypertens. 2020;38(11):2161–2168. PMID 32694334. DOI 10.1097/HJH.0000000000002564.
- Kaypakli O, Özgeyik M. The effect of heart rate and pulse pressure on mean arterial pressure: the combined formula for calculation of mean arterial pressure. Blood Press Monit. 2021;26(5):373–379. PMID 34054029. DOI 10.1097/MBP.0000000000000548.
- Prescott HC, Antonelli M, Alhazzani W, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2026. Crit Care Med. 2026. DOI 10.1097/CCM.0000000000007075.
- 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. PMID 24635770. 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. PMID 32049269. PMCID PMC7064880. DOI 10.1001/jama.2020.0930.
FAQ
The formula describes one cardiac-cycle pressure pair. Combining SBP from one time or device with DBP from another can create a pair that was never observed and a misleading estimate.
Sources: [2]
Pulse pressure is SBP minus DBP. For 120/80 mmHg, pulse pressure is 40 mmHg. This page displays that arithmetic alongside the conventional MAP estimate without classifying it.
Sources: [1]
The raw estimate is 80 + (120 minus 80) divided by 3, or 93.333... mmHg. The page displays 93.3 mmHg while retaining the unrounded value internally.
Sources: [1]
Those are technical validation and fixed-decimal display safeguards designed to prevent unit mistakes, overflow, and a positive value being shown as a false zero. They are not healthy, normal, or treatment ranges.
Sources: [1]
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Disclaimer
Educational and informational reference only. Not intended to replace professional medical advice, diagnosis, treatment, or independent verification.