Health

MAP Calculator

Manual SBP/DBP entry, instant MAP, pulse pressure, Shock Index, and SOFA cardiovascular reference.

manual inputformula visiblemmHg / kPaShock Indexsession history

Quick answers

Manual entry

Blood pressure

Free

Unit

Values convert with the toggle.

Optional

Clinical tools

Hidden by default

Shock Index

Shock Index = HR / SBP

--

Enter valid SBP and heart rate to calculate Shock Index.

Session only

Saved readings

Save a valid reading to keep a small session log on this device.

Assessment

Mean arterial pressure

MAP

--

Enter systolic and diastolic pressures above zero.

Pulse pressure

--

Formula

MAP = DBP + 1/3 x (SBP - DBP)

Enter SBP and DBP to see the worked formula.

Reference bands

Critical low-perfusion risk

MAP below 60 mmHg can signal low perfusion risk.

< 60 mmHg

Below common septic-shock target

This sits below the common MAP >= 65 mmHg septic-shock target.

60-64 mmHg

Common adult reference band

A common adult reference band for mean arterial pressure.

65-100 mmHg

Elevated pressure context

Higher MAP can reflect elevated arterial pressure context.

> 100 mmHg

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About this calculator

Method, formulas, and limits.

What this does

Calculates mean arterial pressure (MAP) from systolic and diastolic blood pressure using the standard formula MAP = DBP + 1/3(SBP - DBP). Also computes pulse pressure, Shock Index (when heart rate is provided), maps the result to a reference band (normal, low, or critical), and surfaces SOFA cardiovascular criteria when relevant.

Who it is for

Healthcare professionals, medical students, nurses, paramedics, and anyone in a clinical or educational setting who needs to quickly evaluate hemodynamic status from blood pressure readings with worked formula display and reference thresholds.

How it works

Enter the systolic and diastolic pressures in mmHg or kPa. The calculator instantly displays MAP, pulse pressure, the worked formula substitution, and a reference band. Optionally enter heart rate to calculate Shock Index and save the reading to the session history (stored in browser storage for the current session).

Limitations

The MAP formula is an approximation that assumes a normal heart rate and vascular tone. It may be less accurate in patients with extreme tachycardia, bradycardia, or aortic valve abnormalities. Shock Index is a screening tool for hemodynamic instability, not a substitute for comprehensive clinical assessment. Session history is stored in sessionStorage and is cleared when the browser tab is closed.

Key calculations

Mean Arterial Pressure
MAP = DBP + 1/3 × (SBP - DBP). The formula approximates the average arterial pressure throughout the cardiac cycle. The calculator shows both the formula and the worked substitution with your values.
Pulse Pressure
Pulse pressure = SBP - DBP. This represents the difference between systolic and diastolic pressure and is an indicator of arterial stiffness and cardiac output. Normal pulse pressure is around 40 mmHg.
Shock Index
SI = HR / SBP. A Shock Index above 1.0 may indicate hemodynamic instability or compensated shock. The calculator computes this automatically when heart rate is entered. Note: SI uses the original SBP value, not MAP.
Unit Conversion
mmHg to kPa: multiply mmHg × 0.133322. kPa to mmHg: multiply kPa × 7.50062. The calculator converts both SBP and DBP when the unit toggle is switched, keeping the MAP calculation aligned with the chosen unit.

Reference ranges

Normal MAP
70–100 mmHg is the generally accepted normal range for adults. Values above 60 mmHg are typically needed to perfuse vital organs. The calculator marks 65–100 mmHg as the standard reference band.
Low MAP (60–69 mmHg)
MAP in this range indicates reduced organ perfusion pressure and may require clinical attention. The calculator labels this as a low-MAP band distinct from critical values, helping clinicians identify borderline cases quickly.
Critical MAP (below 60 mmHg)
MAP below 60 mmHg is considered critical and is typically associated with inadequate tissue perfusion and organ failure risk. This threshold triggers the SOFA cardiovascular reference note in the result.
Pulse Pressure
Normal pulse pressure is 30–50 mmHg. Wide pulse pressure (>60 mmHg) may suggest aortic regurgitation, atherosclerosis, or hyperthyroidism. Narrow pulse pressure (<30 mmHg) may indicate cardiac tamponade, heart failure, or hypovolemia.

How to use it

  1. 1.Enter SBP and DBPType the systolic and diastolic pressures exactly as measured.
  2. 2.Pick the unitUse mmHg or kPa, and switch only if your source reading uses the other unit.
  3. 3.Read the resultReview MAP, pulse pressure, the worked formula, and the active reference band.
  4. 4.Open clinical tools only if neededUse the collapsed Shock Index and history block when you want a bedside follow-up view.

MAP = DBP + 1/3 × (SBP - DBP). This formula estimates the average arterial pressure during a single cardiac cycle by weighting diastole more heavily than systole, since the heart spends about two-thirds of the cycle in diastole. The calculator displays both the raw formula and the worked substitution using your actual values so you can verify the math.

A common adult reference band is 65–100 mmHg for normal perfusion. The calculator separates the low range into two bands: 60–64 mmHg (borderline low) and below 60 mmHg (critical). This follows standard clinical teaching that MAP must stay above 60 mmHg to perfuse the coronary arteries and kidneys adequately.

Yes. When you switch between mmHg and kPa, both the SBP and DBP inputs are converted automatically using the standard conversion factor (1 mmHg = 0.133322 kPa). The MAP and pulse pressure results update to stay aligned with the chosen unit. This is useful when working with devices or records that report in different units.

The SOFA (Sequential Organ Failure Assessment) score uses a MAP below 70 mmHg as the threshold for the cardiovascular component, assigning points when vasopressors are required to maintain MAP above this level. The calculator surfaces this reference when your result drops below 70 mmHg, giving clinical context without scoring the full SOFA assessment.

No. This version stays focused on manual MAP calculation, reference band display, and session-only history tracking. It does not include a qSOFA calculation module, vasopressor dosing guidance, or medication recommendations. The calculator is designed as a quick bedside reference tool rather than a comprehensive clinical decision support system.

Shock Index is calculated as heart rate divided by systolic blood pressure (HR / SBP). A value above 1.0 is traditionally considered abnormal and may suggest hemodynamic instability or early compensated shock. The calculator computes this when you enter a heart rate. Like MAP, Shock Index is a screening tool and should be interpreted alongside the full clinical picture.

Pulse pressure is the difference between systolic and diastolic pressure (SBP - DBP). A normal pulse pressure is 30–50 mmHg. A wide pulse pressure (over 60 mmHg) can indicate aortic regurgitation, arterial stiffness, or hyperthyroidism. A narrow pulse pressure (under 30 mmHg) may suggest cardiac tamponade, heart failure, or significant blood loss. The calculator displays pulse pressure alongside MAP for quick reference.

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