Enter systolic and diastolic pressure

Type the two numbers from a blood-pressure reading in mmHg: systolic (the higher, top number) and diastolic (the lower, bottom number). Diastolic must be below systolic. The calculator updates instantly as you type, or click a preset — Normal, Hypotensive, Hypertensive, or Low MAP / shock — to fill a realistic scenario.

2

Read the MAP and its band

The headline shows mean arterial pressure in mmHg, with a colour-coded band: Low (perfusion risk), Low-normal, Normal (70–100), Elevated, or High. The stat cells also show pulse pressure and, if you entered a heart rate, the rate-pressure product. The 'Where MAP sits' chart plots diastolic, MAP, and systolic on one scale so you can see MAP fall below the midpoint.

3

Check perfusion thresholds

Open the Interpretation tab for the full MAP band table and the settings where MAP matters most — shock, sepsis, ICU, and brain or kidney perfusion. It also explains the ⅓ weighting: why diastolic counts roughly twice as much as systolic in the estimate.

4

Review pulse pressure

The Pulse Pressure tab breaks out SBP − DBP and classifies it as narrow (under ~40), normal (40–60), or wide (over ~60). Wide pulse pressure often reflects arterial stiffening with age; narrow pulse pressure can accompany low stroke volume. Use Share or Copy to save a reading — your numbers are encoded in the URL.

Mean arterial pressure (standard estimate)

MAP = DBP + ⅓ × (SBP − DBP) = (SBP + 2 × DBP) ÷ 3

The widely used bedside estimate of mean arterial pressure. The two forms are algebraically identical. SBP is systolic and DBP is diastolic pressure, both in mmHg; MAP is returned in mmHg.

Pulse pressure

Pulse pressure = SBP − DBP

The difference between systolic and diastolic pressure. It reflects stroke volume and the stiffness of the large arteries. Typical adult pulse pressure is about 40–60 mmHg.

Rate-pressure product (context)

RPP = SBP × heart rate

An optional proxy for myocardial oxygen demand (cardiac workload). It is shown for context when a heart rate is entered and does not change the MAP value.

Reviewed by Calculover Editorial Review Updated 2026-06-13 3 sources Methodology & limitations

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Author: {{^authorProfileUrl}}Calculover Editorial Team{{/authorProfileUrl}} - Editor

Owner: Calculover Editorial Team - Editorial owner

Reviewer: Calculover Editorial Review - Medical-source review

Last reviewed: 2026-06-13

Last verified: 2026-06-13

Data effective: 2026-06-13

Methodology

The Mean Arterial Pressure Calculator applies the standard clinical estimate MAP = (SBP + 2·DBP)/3, equivalently DBP + ⅓(SBP − DBP), to the systolic and diastolic values entered by the user (mmHg). Pulse pressure is computed as SBP − DBP and, when a heart rate is provided, the rate-pressure product as SBP × HR. Interpretation bands (MAP < 60 perfusion-risk, 60–69 low-normal, 70–100 normal, 101–110 elevated, > 110 high; pulse pressure narrow < 40, normal 40–60, wide > 60) are general adult reference ranges drawn from standard physiology and critical-care references, not patient-specific diagnostic thresholds.

Assumption: Systolic and diastolic values are entered in mmHg for the same reading, and diastolic is lower than systolic.

Assumption: The ⅓-weighting estimate assumes a roughly normal resting heart rate; at high heart rates the true MAP drifts toward the simple average of systolic and diastolic.

Assumption: The user wants a screening estimate and interpretation context, not a diagnosis, treatment plan, or dosing decision.

Limitations & guidance

A MAP estimated from an arm cuff is an approximation of the value an invasive arterial line would report, and the formula is least accurate at very high heart rates.

Interpretation bands are general adult reference ranges; targets differ by patient, condition, and care setting (for example sepsis protocols commonly target MAP ≥ 65 mmHg).

This tool does not diagnose, monitor, or guide treatment of any condition. Do not make medical decisions based on its output.

Professional guidance: The Mean Arterial Pressure Calculator is for health education and screening only. It provides an estimate, not medical advice, diagnosis, treatment, or a substitute for care from a licensed healthcare professional. A cuff-derived MAP is an approximation; always rely on a qualified clinician for medical decisions.

Primary sources

DeMers D, Wachs D. Physiology, Mean Arterial Pressure. StatPearls. NCBI Bookshelf. - StatPearls / NCBI Bookshelf

Evans L, Rhodes A, Alhazzani W, et al. Surviving Sepsis Campaign: International Guidelines (MAP ≥ 65 mmHg target). Crit Care Med. 2021. - Critical Care Medicine

Homan TD, Bordes SJ, Cichowski E. Physiology, Pulse Pressure. StatPearls. NCBI Bookshelf. - StatPearls / NCBI Bookshelf

Mean arterial pressure (MAP) The average pressure in a person's arteries during one cardiac cycle, in mmHg. It is the pressure that actually drives blood into the tissues, so it is a key measure of organ perfusion.

Systolic pressure (SBP) The higher (top) blood-pressure number — the peak arterial pressure while the heart contracts and ejects blood. Measured in mmHg.

Diastolic pressure (DBP) The lower (bottom) number — the arterial pressure between heartbeats, while the heart relaxes and fills. Measured in mmHg. It must be below systolic for a valid reading.

Pulse pressure Systolic minus diastolic pressure (SBP − DBP). A typical adult value is 40–60 mmHg; persistently wide values often signal arterial stiffening.

Perfusion The delivery of blood to the tissues. Adequate perfusion of the brain, heart, and kidneys generally requires a MAP of roughly 60 mmHg or more.

The ⅓ (one-third) weighting Because the heart spends about two-thirds of each cycle in diastole at rest, the time-averaged pressure sits closer to diastolic — hence MAP = DBP + ⅓ (SBP − DBP) rather than the simple average.

Show all 8 terms

Rate-pressure product (RPP) Systolic pressure multiplied by heart rate (SBP × HR), a rough index of how hard the heart muscle is working and of its oxygen demand.

Vasopressor A medication that raises blood pressure by constricting blood vessels. In critical care, vasopressors are often titrated to keep MAP at or above a target such as 65 mmHg.

🩺

Maria, 34 — routine check

Normal reading, 120/80

Systolic 120 mmHg Diastolic 80 mmHg MAP 93.3 mmHg Pulse pressure 40 mmHg

A textbook 120/80 reading gives MAP = (120 + 2×80)/3 = 93.3 mmHg, comfortably inside the normal 70–100 mmHg band. Notice MAP is 93, not the simple midpoint of 100 — the diastolic value pulls it down because diastole lasts longer. Pulse pressure of 40 mmHg is right at the lower end of normal.

🚑

Dev, 58 — septic in the ED

Low MAP, 90/45

Systolic 90 mmHg Diastolic 45 mmHg MAP 60 mmHg Pulse pressure 45 mmHg

A systolic of 90 can look 'okay' at a glance, but the MAP is exactly 60 mmHg — right at the threshold where organ perfusion becomes a concern. Many sepsis protocols target a MAP of at least 65 mmHg, so this reading would prompt fluids and close monitoring. This is why critical-care teams watch MAP, not just the systolic number.

❤️

Eleanor, 71 — stiff arteries

Wide pulse pressure, 160/70

Systolic 160 mmHg Diastolic 70 mmHg MAP 100 mmHg Pulse pressure 90 mmHg

MAP here is 100 mmHg — at the top of the normal band — but the pulse pressure of 90 mmHg is markedly wide. Wide pulse pressure with a high systolic and a relatively low diastolic is a classic pattern of large-artery stiffening with age (isolated systolic hypertension), and is worth discussing with a clinician even when the MAP itself looks acceptable.

Mean arterial pressure is the single number that best captures the pressure actually pushing blood into your organs. It is more informative than systolic pressure alone in shock, sepsis, and intensive care, where keeping MAP above a threshold is a treatment goal. This guide explains what MAP is, why the formula weights diastolic pressure twice as heavily as systolic, how to read pulse pressure alongside it, and where the cuff estimate falls short.

What MAP is and why the ⅓ weighting

Mean arterial pressure is the average arterial pressure across a full cardiac cycle — the effective driving pressure for blood flow into the tissues. The bedside estimate is MAP = DBP + ⅓ (SBP − DBP), which is the same as (SBP + 2·DBP)/3.

The reason MAP is not just the average of systolic and diastolic is timing. At a normal resting heart rate the heart spends roughly two-thirds of each beat in diastole (relaxed, lower pressure) and only one-third in systole (contracting, higher pressure). Because the lower diastolic pressure is present for longer, the time-averaged pressure lands closer to diastolic — so diastolic is weighted about twice as much as systolic in the estimate.

Why MAP matters more than systolic in critical care

Organ perfusion depends on mean pressure, not on the systolic peak. A MAP below about 60 mmHg risks inadequate blood flow to the brain, heart, and kidneys; sustained low MAP can cause ischemic injury. That is why intensive-care and sepsis guidelines commonly set a MAP target — frequently at least 65 mmHg — and titrate fluids and vasopressors to reach it.

Two readings with the same systolic can have very different MAPs depending on the diastolic value, and therefore very different perfusion. A patient at 90/45 (MAP 60) is in a different place than one at 90/70 (MAP ~77), even though both have a systolic of 90. Tracking MAP catches that difference; tracking systolic alone misses it.

Pulse pressure and the limits of a cuff estimate

Pulse pressure — systolic minus diastolic — complements MAP. A typical adult value is 40–60 mmHg. Wide pulse pressure (over ~60) most often reflects stiffening of the large arteries with age, and can also accompany aortic regurgitation or hyperthyroidism. Narrow pulse pressure (under ~40) can occur with low stroke volume, significant blood loss, or heart failure, though it is also common simply when overall pressure is low.

Two caveats. First, the ⅓ formula assumes a roughly normal resting heart rate; at high heart rates diastole shortens and true MAP rises toward the simple average, so the estimate drifts. Second, a MAP derived from an arm cuff is an approximation of the value an invasive arterial line would report. For these reasons, use this calculator as a screening and educational aid — not as a basis for medical decisions, which belong with a qualified clinician.

How is mean arterial pressure calculated?+

The standard bedside estimate is MAP = diastolic + ⅓ × (systolic − diastolic), which is the same as (systolic + 2 × diastolic) ÷ 3. For a 120/80 reading that gives (120 + 160) ÷ 3 = 93.3 mmHg. The calculator also reports pulse pressure (systolic − diastolic).

Why is diastolic weighted twice as much as systolic?+

At a normal resting heart rate the heart spends about two-thirds of each cardiac cycle in diastole and only one-third in systole. Because the lower diastolic pressure lasts longer, the time-averaged pressure sits closer to it — so the formula gives diastolic roughly double the weight of systolic. At high heart rates diastole shortens and the true MAP rises toward the simple average, which is one reason the estimate is an approximation.

What is a normal MAP, and what is too low?+

A typical adult MAP is about 70–100 mmHg. A MAP below roughly 60 mmHg is generally considered too low to reliably perfuse vital organs, and in acute care many protocols target a MAP of at least 65 mmHg. A persistently high MAP (above ~110 mmHg) reflects extra load on the heart and vessels. These are general reference ranges, not diagnostic thresholds.

What does pulse pressure tell me?+

Pulse pressure is systolic minus diastolic, normally about 40–60 mmHg. A wide pulse pressure (over ~60) most often signals stiffening of the large arteries with age and can also accompany aortic regurgitation or hyperthyroidism. A narrow pulse pressure (under ~40) can occur with low stroke volume, blood loss, or heart failure. It is a clue to interpret with the rest of the clinical picture.

Why does my MAP look low even when systolic seems fine?+

Because MAP depends heavily on diastolic pressure. A reading like 90/45 has a 'normal-ish' systolic but a MAP of only 60 mmHg, because the low diastolic drags the average down. This is exactly why clinicians watch MAP rather than systolic alone — it captures perfusion that the top number can miss.

Is a cuff MAP as accurate as an arterial line?+

No. A MAP estimated from an arm-cuff systolic and diastolic is an approximation of the value a direct (invasive) arterial line would measure, and the ⅓ formula assumes a roughly normal heart rate. The estimate is useful for screening and education, but it is not a substitute for invasive monitoring or clinical judgement.

Can I share my MAP result?+

Yes. The calculator encodes your systolic, diastolic, and heart rate into the page URL, so copying the link (or using the Share button) reproduces the exact reading for someone else. You can also Copy a text summary or export a CSV.

Mean Arterial Pressure (MAP) Calculator

How to Use This Calculator

Enter systolic and diastolic pressure

Read the MAP and its band

Check perfusion thresholds

Review pulse pressure

Formula & Methodology

Trust, Methodology & Sources

Key Terms Explained

Real-World Examples

Maria, 34 — routine check

Dev, 58 — septic in the ED

Eleanor, 71 — stiff arteries

Understanding Mean Arterial Pressure (MAP)

What MAP is and why the ⅓ weighting

Why MAP matters more than systolic in critical care

Pulse pressure and the limits of a cuff estimate

Frequently Asked Questions

Mean Arterial Pressure (MAP) Calculator

How to Use This Calculator

Enter systolic and diastolic pressure

Read the MAP and its band

Check perfusion thresholds

Review pulse pressure

Formula & Methodology

Trust, Methodology & Sources

Key Terms Explained

Real-World Examples

Understanding Mean Arterial Pressure (MAP)

What MAP is and why the ⅓ weighting

Why MAP matters more than systolic in critical care

Pulse pressure and the limits of a cuff estimate

Frequently Asked Questions

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