Mean Arterial Pressure Calculator
Estimate MAP from systolic and diastolic blood pressure using the one-third pulse-pressure formula. Keep the original reading, the pressure difference and the calculation together.
Pressure is not a measurement of blood flow. This estimate cannot confirm organ perfusion, diagnose shock or tell you that a blood-pressure reading is safe.
Use the calculatorTurn One BP Reading Into a MAP Estimate
Enter both numbers from the same blood-pressure reading, in mmHg.
Your pressure summary will appear here
Enter the two BP numbers. The result shows the estimate and its arithmetic, without a safe / unsafe badge.
MAP is not the midpoint
At 120/80, the one-third estimate is 93.33 mmHg; the simple midpoint is 100.
Equal MAP can hide a different BP
120/80 and 160/60 both estimate 93.33 mmHg, but their pulse pressures differ.
A hospital target is not a home diagnosis
A treatment target used in septic shock cannot certify a home reading as safe.
Your blood-pressure calculation
One-third pulse-pressure approximation
No perfusion verdict: This number does not measure blood flow or oxygen delivery, rule out shock, classify hypertension or set a treatment target. Review both original BP numbers and any symptoms.
Two decimal places show the arithmetic, not measurement accuracy. The formula assumes a normal heart rate and is not an arterial-waveform measurement.
Medical disclaimer: This is an educational estimate from adult blood-pressure entries. It is not a diagnostic or monitoring device and does not replace medical assessment, a clinical monitor or your care team’s targets. Do not change medicines, fluids or salt intake based on this result. Children, pregnancy and critical illness need their own clinical assessment.
Follow the arithmetic from the original reading
Averaging the high and low numbers equally is a different calculation. This page uses the one-third rule and does not reconstruct a beat-by-beat arterial waveform.
How the one-third MAP estimate is calculated
Two equivalent formulas give the same estimate. Neither one measures organ blood flow.
| Quantity | Calculation | What it describes |
|---|---|---|
| Pulse pressure (PP) | SBP − DBP | The difference between the two entered pressures; not a pulse rate. |
| Estimated MAP | DBP + (SBP − DBP) ÷ 3 | Equivalent to (SBP + 2 × DBP) ÷ 3. A conventional approximation, not a measured time average. |
| Simple midpoint · comparison only | (SBP + DBP) ÷ 2 | Weights both endpoints equally. This is not the MAP method used here. |
Formula definitions: ACC/AHA 2017 guideline, Table 4. This historical reference supports the arithmetic, not current treatment thresholds. Primary research comparing MAP algorithms explains why an estimate should not be treated as an exact measurement.
120/80 → MAP 93.33 mmHg
Pulse pressure: 40 mmHg. Add one-third of 40 to the diastolic value of 80. This fictional reading is an arithmetic example, not a personal target.
160/60 → MAP 93.33 mmHg
Pulse pressure: 100 mmHg. The MAP matches Example 1, although the systolic and diastolic readings do not. Equal MAP does not establish equal clinical meaning.
90/50 → MAP 63.33 mmHg
Pulse pressure: 40 mmHg. This result does not diagnose shock or prescribe fluids. Symptoms, repeat measurements and the clinical situation still matter.
What a derived pressure number leaves out
Read MAP alongside the original BP, the measurement method and the clinical situation.
Why diastolic pressure receives more weight
The conventional rule gives diastolic pressure twice the weight of systolic pressure. It approximates the time average over a cardiac cycle at a normal heart rate; it is not the ordinary average of two endpoints. A changed waveform or heart rate can change the relationship.
Keep systolic and diastolic values beside MAP
The same MAP can be generated by several BP pairs. A systolic reading of 160 with a diastolic reading of 60 produces the same estimate as 120/80. A single derived value can hide an important difference in the original measurement.
A pressure estimate cannot verify organ perfusion
Blood flow also depends on resistance and the pressure gradient across a vascular bed. Oxygen delivery adds further factors. This page has no measurements of those quantities and cannot conclude that the kidneys, brain or heart are receiving enough blood.
Why 65 mmHg needs its clinical context
The 2026 Surviving Sepsis Campaign recommends an initial MAP target of 65 mmHg for adults with septic shock over higher targets. It also suggests 60–65 mmHg initially for adults aged 65 or older in that setting. These clinician-managed targets are not universal home safety cutoffs.
An estimated MAP and a monitor MAP can differ
An arterial monitor uses waveform information; an automated cuff can use its own algorithm. Recalculating from displayed, rounded systolic and diastolic values may produce a different number. This calculator cannot verify which measurement or device is correct.
A useful input starts with a usable measurement
Use a validated upper-arm monitor, a correctly sized cuff, supported arm at heart level and the measurement instructions supplied by your care team. Record the original pair and its time. Recalculation cannot correct a cuff-size, posture or transcription error.
Do not use this as a shock or hypertension classifier
There are no green normal zones or red shock diagnoses here. The estimate alone cannot rule either condition in or out. A reassuring-looking MAP must not override a very high original BP, concerning symptoms or your care team’s instructions.
Arithmetic does not choose fluids or medication
A lower number is not an instruction to drink extra water, take salt or adjust medicine. A higher number is not a prescription either. Seek professional interpretation for unexpected readings, and urgent help for severe or sudden symptoms.
Verify the hospital-target context in the 2026 Surviving Sepsis Campaign guideline. For measurement technique, use the AHA home blood-pressure guide. For very high readings and symptoms, see AHA urgent-care guidance. This tool does not set an individual target.
Helpful resources
Use these tools for different questions, and check the sources behind this page’s method and limitations.
Useful resources
References support the method and context; they do not endorse this website. Bhavin Sheth is credited for maintenance, not medical review. This implementation has not been independently clinically validated.
Questions about MAP, pulse pressure and clinical targets
Understand the approximation before attaching a medical meaning to it.
What formula does this MAP calculator use?
It uses estimated MAP = DBP + (SBP − DBP) ÷ 3, equivalent to (SBP + 2 × DBP) ÷ 3. Both inputs and the output are in mmHg. This conventional approximation assumes a normal heart rate.
Why is MAP not simply the average of systolic and diastolic?
The simple midpoint weights the two endpoints equally. This calculator instead uses the one-third pulse-pressure rule as an approximation of the time average over a cardiac cycle. At 120/80, the midpoint is 100 but estimated MAP is 93.33 mmHg.
Can two different blood-pressure readings have the same MAP?
Yes. Both 120/80 and 160/60 produce an estimated MAP of 93.33 mmHg. Their pulse pressures are 40 and 100 mmHg. Equal MAP does not make the original readings clinically interchangeable.
Does a MAP above 65 mean my organs are getting enough blood?
No. This calculator does not measure organ blood flow, oxygen delivery or the other factors involved in perfusion. A derived MAP cannot certify adequate perfusion or exclude shock.
Where does the 65 mmHg target come from?
The 2026 Surviving Sepsis Campaign recommends an initial MAP target of 65 mmHg for adults with septic shock over higher targets. It also suggests 60–65 mmHg initially for those aged 65 or older in that setting. These are clinical treatment targets, not universal home safety cutoffs.
Why can my monitor display a different MAP?
A monitor can use waveform information or its own estimation algorithm. This page uses a fixed formula applied to the systolic and diastolic numbers you enter, which may themselves be rounded. It does not replace the monitor or determine which result is correct.
Can I use this to diagnose high blood pressure or shock?
No. This is an educational calculation without diagnostic categories. Keep both original blood-pressure numbers, symptoms, repeat readings and your care team’s advice in view.
What does pulse pressure mean here?
Pulse pressure is systolic minus diastolic pressure, in mmHg. It is a pressure difference, not pulse rate in beats per minute and not a stand-alone diagnosis.
Should I change water, salt or medicine to change MAP?
No. Do not change fluids, salt intake or medication based on this page. Unexpected readings need professional interpretation. Severe or sudden symptoms need urgent medical assessment rather than a calculator result.
Are my blood-pressure entries uploaded or saved?
This calculator script keeps entries in browser memory without uploading them or saving them to browser storage. Other website scripts can make their own requests; this statement applies to the calculator script only.