Pressure Unit Conversion Guide
Pressure is expressed in many units depending on the field: pascals in science, bar in meteorology and industry, PSI (pounds per square inch) in the US for tyres and plumbing, atmospheres in chemistry, and mmHg in medicine for blood pressure. All convert to pascals through fixed factors.
Google ad
Formula
Pressure Converter
Convert pressure between Pascal, Bar, PSI, atm, and mmHg.
Google ad
Worked Example
Given:
Related Calculators
FAQs
What is normal blood pressure in different units?
Blood pressure is measured in mmHg (millimetres of mercury). Normal blood pressure is about 120/80 mmHg — systolic/diastolic. In pascals this is 15,998/10,665 Pa. In PSI it is 1.74/1.16 PSI. The mmHg unit persists in medicine due to historical use of mercury manometers.
What is tyre pressure typically measured in?
In the US: PSI (typically 30–35 PSI for passenger cars). In Europe and Australia: bar (typically 2.1–2.5 bar) or kPa. 30 PSI = 2.07 bar = 207 kPa. Always check your vehicle's door placard or manual for the correct specification — over and under-inflation both reduce safety and fuel efficiency.
What is gauge pressure vs absolute pressure?
Absolute pressure includes atmospheric pressure in the measurement. Gauge pressure measures pressure above or below atmospheric (0 gauge = 1 atm absolute). Tyre pressure is gauge pressure — a flat tyre at '0 PSI gauge' still contains air at atmospheric pressure (14.7 PSI absolute). Vacuum gauges measure below atmospheric as negative gauge pressure.