mPas

mPas is an abbreviation that can refer to either milliPascals (mPa), a unit of pressure, or millipascal-seconds (mPa·s), a unit of dynamic viscosity. The intended meaning is usually clear from the context, but the two are distinct quantities and should not be confused.

As a unit of pressure, 1 mPa equals 10^-3 pascals. Since a pascal is a relatively small unit of pressure, milliPascals are rarely used for everyday measurements. More common pressure units are pascals, kilopascals (kPa), or megapascals (MPa). Nevertheless, mPa can appear in highly sensitive vacuum measurements, microfluidics, or other contexts where very small pressure differences are relevant. For reference, 101,325 Pa (one standard atmosphere) is 101,325,000 mPa.

As a unit of dynamic viscosity, mPa·s (often written as mPa·s rather than mPas) is the millipascal-second. It is equivalent to 10^-3 pascal-seconds. This is the most common way to express viscosity in the practical range for liquids. For example, water at room temperature has a dynamic viscosity of about 1.0 mPa·s (0.001 Pa·s). Other liquids can have viscosities significantly higher or lower, measured in mPa·s.

Notation considerations: when referring to pressure, the standard SI unit is the pascal (Pa), with prefixes such as mPa, kPa, or MPa. When referring to viscosity, the standard SI unit is the pascal-second (Pa·s), with millipascal-seconds (mPa·s) used for low-viscosity liquids. In literature, “mPas” may be encountered as a shorthand, but precision usually requires writing mPa or mPa·s explicitly.