millitorr

Millitorr is a unit of pressure used in vacuum technology. It represents one thousandth of a torr and is commonly abbreviated mtorr or mTorr. The torr is defined as 1/760 of an atmosphere, making it closely related to the pascal: 1 torr is about 133.322 pascals. Consequently, 1 millitorr equals about 0.133 pascals.

In terms of relationships with other pressure units, 1 torr equals 1000 millitorr, and 1 atmosphere is 760 torr, or roughly 101,325 pascals. The millitorr is therefore a convenient unit for describing low to moderate vacuum levels without switching to smaller prefixes such as microns or pascals.

Usage and context regularly appear in vacuum technology and instrumentation. Millitorr is commonly used to express pressures in the rough vacuum range, roughly from atmospheric pressure down to around 0.001 torr. For higher or lower ranges, engineers may use other units or prefixes, but mtorr remains a standard in the non-ultra-high vacuum domain. Vacuum gauges and controllers often display readings in torr or mtorr, with conversions to pascals or atmospheres available as needed.

Notes: mtorr is not an SI unit, but it is widely recognized in the field. The term is typically written as mtorr or mTorr, and many instrument datasheets and lab reports use this convention to describe vacuum pressures in the low to mid-range.