Vacuum range

Pressure in mbar

Molecules/cm3

Mean free path

Ambient pressure

1013.25

2.7 × 1019

68 nm

Low vacuum

300...1

1019...1016

0.1 µm...100 µm

Medium vacuum

1...10−3

1016...1013

0.1 mm...100 mm

High vacuum

10−3...10−7

1013...109

100 mm...1 km