The vacuum pressure unit millibar (mbar) is a long‑standing favorite in the European vacuum industry and remains widely used across vacuum technology and pressure measurement applications. Its origins go back to 1906, when Norwegian meteorologist and weather‑forecasting pioneer Vilhelm Bjerknes introduced both the bar and millibar units, marking a major milestone in the standardization of atmospheric pressure measurement.
1 mbar equals 100 pascal, which also makes it identical to one hectopascal (hPa). This conversion is frequently referenced in engineering, vacuum science, and meteorology.
Historically, the millibar was the dominant unit in weather forecasting and climate data reporting, appearing in meteorological charts and early broadcast forecasts. But as international standards evolved, the SI unit hectopascal officially replaced the millibar in modern meteorological science, ensuring alignment with global measurement standards and improving consistency across scientific disciplines.
Still, despite this formal shift, the millibar continues to have a strong presence in vacuum engineering, industrial pressure systems, legacy instrumentation, and scientific literature.
