The formula assumes a normal heart rate, and at high heart rates the true MAP is closer to the average of systolic and diastolic. Cuff measurements have error. A single reading does not diagnose anything, since blood pressure varies during the day.
Medical decisions rely on repeated measurements and clinical context.
Enter the systolic and diastolic blood pressure from the same reading, in millimeters of mercury. Take the reading seated and rested after five minutes, with the arm at heart level and the correct cuff size, and average two or three readings. Home monitors work for tracking, though clinicians use their own measurements in a clinical setting.
The formula is diastolic plus one third of the pulse pressure.
Mean Arterial Pressure: worked example
| Systolic pressure (mmHg) | 120 |
|---|---|
| Diastolic pressure (mmHg) | 80 |
| Mean arterial pressure (mmHg) | 93.3 |
| Pulse pressure (mmHg) | 40 |
Mean Arterial Pressure: formula
Common error: Averaging the two numbers. The heart spends longer relaxed than pumping, so the simple average of 100 overstates the true mean.
Mean Arterial Pressure: changing Systolic pressure (mmHg)
| Systolic pressure (mmHg) | Mean arterial pressure (mmHg) | Pulse pressure (mmHg) |
|---|---|---|
| 96 | 85.3 | 16 |
| 108 | 89.3 | 28 |
| 120 (example) | 93.3 | 40 |
| 132 | 97.3 | 52 |
| 144 | 101.3 | 64 |
Mean Arterial Pressure: compare input ranges
| Input | Tested from | To | Mean arterial pressure (mmHg): low input | Mean arterial pressure (mmHg): high input | Swing |
|---|---|---|---|---|---|
| Diastolic pressure (mmHg) | 72 | 88 | 88 | 98.7 | 10.7 (11%) |
| Systolic pressure (mmHg) | 108 | 132 | 89.3 | 97.3 | 8 (8.6%) |
Mean Arterial Pressure: individual input comparisons
| Input | Value | Mean arterial pressure (mmHg) | Pulse pressure (mmHg) |
|---|---|---|---|
| Systolic pressure (mmHg) | 96 | 85.3 | 16 |
| 108 | 89.3 | 28 | |
| 120 | 93.3 | 40 | |
| 132 | 97.3 | 52 | |
| 144 | 101.3 | 64 | |
| Diastolic pressure (mmHg) | 64 | 82.7 | 56 |
| 72 | 88 | 48 | |
| 80 | 93.3 | 40 | |
| 88 | 98.7 | 32 | |
| 96 | 104 | 24 |
Mean Arterial Pressure: combined input changes
| Systolic pressure (mmHg) / Diastolic pressure (mmHg) | 64 | 80 | 96 |
|---|---|---|---|
| 96 | 74.7 | 85.3 | 96 |
| 108 | 78.7 | 89.3 | 100 |
| 120 | 82.7 | 93.3 | 104 |
| 132 | 86.7 | 97.3 | 108 |
| 144 | 90.7 | 101.3 | 112 |
Mean Arterial Pressure: which assumptions move the result?
Mean Arterial Pressure: values and definitions
| Quantity and definition | Value used |
|---|---|
| Systolic pressure (mmHg) | 120 |
| Diastolic pressure (mmHg) | 80 |
| Mean arterial pressure (mmHg) | 93.3 |
| Pulse pressure (mmHg) | 40 |
Mean Arterial Pressure: half and double Diastolic pressure (mmHg)
| Diastolic pressure (mmHg) | Mean arterial pressure (mmHg) |
|---|---|
| 40 | 66.7 |
| 80 | 93.3 |
| 160 | 146.7 |
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Blood pressure has two numbers, but organs feel the average pressure through the cycle. Mean arterial pressure weights the resting phase twice as heavily as the pumping phase, so a reading of 120 over 80 works out to about 93. Pulse pressure is the gap between the two numbers, 40 here, and clinicians watch it because a wide or narrow gap says something on its own.
Use a proper seated reading taken after rest. One reading right after stairs or coffee can shift both numbers.
See related health markers on the cholesterol, GFR and BMI calculators, and heart rate on the max heart rate and target heart rate pages. The body surface area calculator and waist-to-hip page cover body size. Blood-pressure treatment targets depend on the person’s clinical circumstances.
Is the displayed MAP a directly measured time average?
No. It is an approximation from systolic and diastolic values. Heart rate, waveform shape and measurement method affect the comparison with a measured mean.
Can this diagnose hypertension?
No. This arithmetic from one input pair does not replace repeated measurements and a clinical assessment.
What is a normal mean arterial pressure?
This tool estimates MAP from entered systolic and diastolic pressures. A clinical target depends on the patient and setting; a calculated threshold does not establish adequate organ perfusion or a diagnosis. Use correctly measured pressures and clinical assessment rather than treating one arithmetic result as a treatment target.
What is pulse pressure?
Pulse pressure is systolic pressure minus diastolic pressure. It is a calculated difference, not a diagnosis by itself. Measurement conditions, symptoms, prior readings and the clinical situation determine how a clinician interprets it.
Can I diagnose high blood pressure from one reading?
No. Diagnosis requires repeated measurements on different occasions, often including home or 24-hour ambulatory monitoring, and a clinician's assessment.