Calculator for converting between pressure units

The International System of Units (SI) is the only system of measurement with an official status in most countries. The acronym SI is abbreviated from the French Système international (d'unités) and is the current form of the metric system.

For pressure, the SI system’s basic unit is the Pascal (Pa), which is 1 N/m² (Newton per square meter). A newton is equal to the force that would give a mass of one kilogram an acceleration of one metre per second per second (1 kg.m.s⁻²), and is equivalent to 100,000 dynes.

The calculator below can convert between the major pressure units, pascal, kilopascal, bar, millibar, pounds per square inch (psi) and standard atmosphere used in practice. The standard atmosphere is a unit of pressure defined as 101325 Pa (1.01325 bar). It is approximately equal to Earth's atmospheric pressure at sea level.

How to cite this calculator

Mullan, W.M.A. (2020) [On-line] Available from: Accessed: