Which units are used to measure very high pressures in physics?

In the field of physics, particularly when studying high-pressure phenomena, several units are used to quantify extreme conditions. While the pascal (Pa) is the official International System of Units (SI) unit, it is often considered inconveniently small for high-pressure research.12

Consequently, researchers frequently utilize larger multiples of the pascal:

• Gigapascal (GPa): Equivalent to ${10}^9$ pascals or 10,000 bars. This is a standard unit for describing pressures in materials research and planetary science.2
• Terapascal (TPa): Equivalent to ${10}^{12}$ pascals or 10,000,000 bars. This unit is used to describe the extreme pressures found within the interiors of large planets like Jupiter and Saturn.2

Other units, such as the atmosphere (atm) and the bar, are also commonly cited in scientific literature, though they are not SI units. For reference, 1 bar is approximately equal to 1 atmosphere.2