This blood pressure calculator estimates your mean arterial pressure based on your values of systolic and diastolic pressures. You can read more about these determinations below the form.


 

Systolic pressure (SP):*
Diastolic pressure (DP):*

How does this blood pressure calculator work?

This heart function tool can help you determine your blood pressure constants which are the mean arterial pressure (MAP) and pulse pressure (PP), the measures of the perfusion pressure of the heart. You are asked to input the values of the systolic (SP) and diastolic pressure (DP) that are measured in mmHg. You will also receive the status of your blood pressure according to this reading.

The mean arterial pressure (MAP) formula used by the blood pressure calculator is:

MAP ≈ [(2*DP) + SP]/3

The pulse pressure (PP) formula used is:

PP = SP – DP

The calculator returns the blood pressure status reading based on the following ranges for SP and DP:

Blood Pressure Status Systolic (mm Hg) IF Distolic (mm Hg)
Min Max   Min Max
Normal Blood Pressure < 120 and <80
Pre-hypertension 120 139 or 80 89
Stage I High Blood Pressure (Hypertension) 140 159 or 90 99
Stage II High Blood Pressure (Hypertension) 160 180 or 100 110
Hypertensive crisis (where emergency care is required) > 180 or >110

Example calculation

Here are some cases and their corresponding results:

No Systolic pressure (mmHg) Diastolic pressure (mmHg) Result
1 115 70 Mean Arterial Pressure: 85mmHg
Blood Pressure status: Normal pressure
Pulse Pressure (PP): 45mmHg
2 127 85 Mean Arterial Pressure: 99mmHg
Blood Pressure status: Pre-hypertension
Pulse Pressure (PP): 42mmHg
3 145 93 Mean Arterial Pressure: 110mmHg
Blood Pressure status: Hypertension Stage I
Pulse Pressure (PP): 52mmHg
4 170 104 Mean Arterial Pressure: 126mmHg
Blood Pressure status: Hypertension Stage II
Pulse Pressure (PP): 66mmHg

What is blood pressure?

It is one of the vital signs and represents the pressure of the circulating blood on the surface of the blood vessels. It is expressed through the rapport of systolic pressure over diastolic pressure and is measured in millimeters of mercury (mmHg). The first one represents the maximum pressure while beating and the second one is the pressure between beats. BP is under the control of the nervous and endocrine systems and varies with age, activity and health status. Low blood pressure is known as hypotension while pathologically high values are defined as hypertension.

Defining MAP (mean arterial pressure):This value describes the average blood pressure of a person during a single cardiac cycle when blood is pumped from the ventricle into the arteries.

Defining PP (pulse pressure): This describes the difference between the systolic and diastolic pressures and could be translated as the force generated by each of the heart contractions. In the case of resting blood pressure PP is around 40mmHg.

Blood pressure chart

110 HYPERTENSION
100
90 HYPERTENSION STAGE II
80  

pre

HYPERTENSION

STAGE I
70

 

Normal blood pressure

60
50  
40
  70 80 90 100 110 120 130 140 150 160 170

References

1) Hall J. (2015) Guyton and Hall Textbook of Medical Physiology 13th ed. Elsevier Health Sciences

2) Caro CG. (1978) The Mechanics of The Circulation. Oxford [Oxfordshire]: Oxford University Press.

3) Klabunde R. (2005) Cardiovascular Physiology Concepts. Lippincott Williams & Wilkins.

19 Jan, 2015