Blood Pressure Calculator

Created by Joanna Michałowska, PhD candidate
Last updated: Jan 14, 2022

This blood pressure calculator helps you to check if your blood pressure is within the recommended ranges by determining if your blood pressure is normal, too high or too low. In the article below, you will find an explanation on how to calculate blood pressure, what factors can influence it, what hypertension is, and how to use our BP calculator.

What is blood pressure?

Blood pressure is the pressure of circulating blood on the walls of the blood vessels. It is usually determined by two values:

  • systolic blood pressure - the maximum BP during one heartbeat, when the heart contracts; and
  • diastolic blood pressure - the minimum BP in between two heartbeats, when the heart is at rest.

Systolic blood pressure is always higher than the diastolic measurement and is the first number you see in a blood pressure reading.

How to calculate blood pressure?

Blood pressure is most commonly measured using a sphygmomanometer, which is also known as a blood pressure monitor or gauge. To make sure that your results is reliable, you should:

  • sit still - make sure that you have been at rest for at least 5 minutes before the measurement and have not exercised for at least 30 minutes before;
  • refrain from caffeine and cigarettes for at least 30 minutes before the measurement;
  • sit correctly - your back should be straight and supported and your arms should rest on a flat surface with the upper arm at heart level;
  • always take the measurement at the same time of the day;
  • take at least two measurements each time and record them somewhere; and
  • always place the blood pressure monitor on your skin, do not take measurements over your clothes.

Blood pressure calculator

This blood pressure calculator uses two different guidelines, each with there own values for normal and abnormal blood pressure:

  1. American - A Report of the American College of Cardiology (ACC) and American Heart Association (AHA) Task Force (2017)
  2. European - Task Force of European Society of Cardiology (ESC) and the European Society of Hypertension (ESH) (2018)

The classification of normal blood pressure differs slightly depending on the guideline and should be lower than 120/80 mmHg (American guideline) or 130/85 mmHg (European guideline). Both guidelines also define intermediate thresholds, like elevated, high normal, and optimal blood pressure.

Is my blood pressure too high?

In adults, blood pressure can be considered high if it's greater than 130/80 mmHg or 140/90 mmHg, depending on the guideline. There are many risk factors related to high blood pressure:

  1. Things you cannot change:
  • family history of high blood pressure;
  • age - the older you are, the more likely you are to have high blood pressure;
  • gender - until age of 64 men are more likely to suffer from hypertension, but after 65 this shifts to women;
  • race - African-Americans tend to develop high blood pressure more often; and
  • chronic kidney disease.
  1. Thing you do have influence over:

If your blood pressure exceeds the recommended values, your doctor can diagnose you with hypertension and prescribe an appropriate medication.

What is hypertension?

Hypertension is a long-term condition in which the blood pressure is permanently elevated. It usually does not cause any symptoms, but is considered as a major risk factor of many diseases, including:

Moreover, blood pressure that exceeds 180/120 mmHg can be considered as a hypertensive crisis, and it is a life-threatening condition. Contact your doctor immediately.

Is my blood pressure too low?

A normal blood pressure is usually less than 120/80 mmHg, but can it be too low? Low blood pressure (hypotension) can be defined as blood pressure below 90/60 mmHg; however, some people have a low blood pressure all the time, and it is normal for them. Therefore, doctors usually consider low blood pressure as dangerous if it causes noticeable signs and symptoms, such as:

  • dizziness, lightheadedness or nausea;
  • fainting;
  • dehydration;
  • lack of concentration;
  • blurred vision;
  • cold and pale skin; and
  • rapid and shallow breathing.
Joanna Michałowska, PhD candidate
Blood pressure readings are expressed in the following form:
[Systolic]/[Diastolic]: XXX/YY mmHg
American (ACC and AHA)
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