millibar [mbar] Unit Converter

Definition of millibar [mbar] unit

A millibar (mbar) is a unit of pressure equal to 100 pascals (Pa), or one-thousandth of a bar. It represents force distributed over an area and is commonly used to express atmospheric and meteorological pressure.

History of millibar [mbar] unit

The millibar emerged from the bar, a pressure unit introduced in the early twentieth century within the metric system. The prefix “milli-” denotes one-thousandth, making one millibar equal to 0.001 bar. Meteorologists adopted it because its values conveniently matched typical atmospheric pressures: standard sea-level pressure is approximately 1,013.25 millibars. The unit became especially prominent in weather maps, aviation, and marine forecasting. In 1982, the World Meteorological Organization recommended the hectopascal (hPa), numerically identical to the millibar, as the preferred official unit.

Applications of millibar [mbar] unit

Millibars are still widely used in weather reporting, especially in public forecasts, barometric pressure readings, and synoptic charts. Atmospheric pressure around 1,000–1,025 millibars often accompanies ordinary sea-level conditions, while falling values can signal unsettled weather. Although hectopascals are standard in many countries, millibars remain familiar in aviation, marine navigation, and consumer barometers.

Complete list of millibar [mbar] unit conversion