Convert Hectopascal to Atmosphere

One hPa equals 0.0009869232667 atm. This converter allows you to easily convert between Hectopascal and Atmosphere in real time.

Formula

hPa × 0.0009869232667 = atm

Example: 1 hPa = 0.0009869232667 atm

What is Hectopascal?

The hectopascal equals 100 pascals and is the standard unit for atmospheric pressure in meteorology worldwide. Standard atmospheric pressure is 1013.25 hPa, and weather reports use hectopascals when describing high and low pressure systems and typhoon central pressures (such as 950 hPa). One hectopascal is exactly equal to one millibar. The international meteorological community switched from millibars to hectopascals in 1992.

What is Atmosphere?

The standard atmosphere is a unit of pressure defined as exactly 101,325 pascals. It approximates the average atmospheric pressure at sea level on Earth. In diving, pressure increases by roughly 1 atm for every 10 meters of water depth, so at 30 meters the total pressure is about 4 atm. In chemistry, standard conditions for gases are defined at 0 degrees Celsius and 1 atm, making it a fundamental reference in thermodynamics and gas law calculations.