Pressure units vary widely by field, meteorology, tire pressure, medical blood pressure, and vacuum systems each favor different conventions, this converter handles 8 common units in one tool.
How to use this pressure conversion tool
- Enter a value and select your From unit.
- Select your To unit.
- Read the converted result instantly, or tap Swap Units to reverse the direction.
What this tool does
Pressure is measured in the SI unit pascal (Pa), one newton per square meter. This tool converts between 8 common pressure units used across meteorology, engineering, medicine, and everyday contexts, from the pascal itself up through units like PSI, bar, standard atmospheres, torr, and mmHg.
1 atm = 101,325 Pa = 14.696 PSI = 1.01325 bar = 760 torr = 760 mmHg
Why different fields settled on different units
Meteorology traditionally uses millibars (or hectopascals) for atmospheric pressure readings. Tire pressure and many engineering specs in the US use PSI (pounds per square inch). Medical blood pressure readings use mmHg. Vacuum system specifications often use torr. Each convention persisted within its field due to historical instrumentation and the practical scale of the numbers involved, a blood pressure reading in pascals, for instance, would produce awkwardly large numbers compared to the familiar mmHg convention.
Frequently asked questions
Why does blood pressure use mmHg instead of a more common unit?
mmHg (millimeters of mercury) has been the historical convention in medicine since early mercury-column pressure gauges, and the resulting numbers (like 120/80) are a familiar, manageable scale that has persisted even as measurement technology has changed.
How many PSI are in one standard atmosphere?
1 standard atmosphere (atm) equals approximately 14.696 PSI.
