Vacuum Pressure Converter
Convert between vacuum pressure units (Pa, Torr, mbar, atm, psi, micron). Shows vacuum range classification and mean free path at the entered pressure.
Vacuum pressure is expressed in multiple unit systems depending on application and region: Pa (SI), Torr (common in research), mbar (European instrumentation), and microns (µm Hg, used in HVAC and roughing pumps). One micron equals 10−3 Torr or 0.133 Pa. This converter translates any entered pressure into all six common units, classifies the result by vacuum regime (rough / medium / high / ultra-high), and estimates the gas-phase mean free path at that pressure — useful for determining whether molecular flow conditions apply to an optical path or vacuum chamber.
For vacuum system physics — pressure regimes, outgassing rates, pumping system selection, and UV/IR transmission in vacuum — see the Vacuum Science for Optics guide.