Micron or Micrometre of Mercury is a very small pressure unit which is derived from the pressure due to gravity that is generated by a 1 micrometer (1/1000mm) column of liquid mercury. 1 micron of mercury of mercury at zero degrees Celsius equals 0.133322 pascals.

The main use for micrometers of mercury is to measure high vacuum.

The micron of Hg pressure unit is treated as being equal to 1 millitorr, however although the mtorr is a fixed value, the mercury measurement can vary slightly around the world depending what is assumed for the density of mercury and local gravity.

For more information on how Mercury units are derived, please go to our mmHg web page.

Pick a pressure unit conversion factor from the list below for the equivalent value of 1 micron Hg.

Click one one of the units below to find the conversion value to microns of Hg.

Generate many different unit conversions and values of micrometres of Hg using our webpage pressure converter.

View the derivation of µHg from SI units or check a pressure unit against the various ways of describing µHg.

**Low pressure measurement products**

- Low Pressure Range Intrinsically Safe Pressure Transmitters
- -2 to 2 inHg g 4-20mA out intake and exhaust air pressure sensor for building management use
- Negative 500 mmH2O g range 4-20mA output pressure sensor
- 50 mbar ATEX approved air duct pressure sensor

## Conversion Factors

- 0.00000133322 bar
- 0.0000193368 psi
- 0.00133322 mbar
- 0.133322 N/m²
- 0.133322 Pa
- 0.00133322 hPa
- 0.000133322 kPa
- 0.000000133322 MPa
- 0.00000135951 kg/cm²
- 0.0135951 mmH2O 4°C (39.2°F)
- 0.00135951 cmH2O 4°C (39.2°F)
- 0.0000135951 mH2O 4°C (39.2°F)
- 0.000535240 inH2O 4°C (39.2°F)
- 0.0000446033 ftH2O 4°C (39.2°F)
- 0.001 mmHg 0°C (32°F)
- 0.0001 cmHg 0°C (32°F)
- 0.0000393701 inHg 0°C (32°F)
- 0.001000000 Torr
- 1.000000 mTorr
- 0.00000131579 atm
- 0.00000135951 at
- 1.33322 dyn/cm²
- 0.000309388 oz/in²
- 1 µHg 0°C (32°F)
- 0.00000000863249 tsi (uk, long)
- 0.00000000966839 tsi (usa, short)
- 0.00000139225 tsf (usa, short)
- 0.00278450 psf
- 0.00135951 g/cm²

*Please note that the conversion factors above are accurate to 6 significant figures.*

**Low pressure measurement products**

- 1 inH2O dp range wall mounted HEPA air filter pressure gauge with 4-20mA output
- Low Range Voltage Output Pressure Transducers
- 50 mbar ATEX approved air duct pressure sensor
- Intrinsically safe digital gauge for monitoring 300mbar pressure

## Derivation

The calculation below shows how the pressure unit microns of mercury (µHg) is derived from SI Units.

#### Formula

- Pressure = Force / Area
- Force = Mass x Acceleration
- Mass = Density x Volume
- Volume = Area x Height
- Acceleration = Distance / (Time x Time)

#### SI Units

- Mass: kilogram (kg)
- Distance: metre (m)
- Time: second (s)
- Force: newton (N)
- Pressure: pascal (Pa)

#### Input Values

- Density = Mercury Density at 0degC = 13595.1 kg/m³
- Area = 1 m²
- Height = 1 µm = 0.000001 m
- Acceleration = Standard Gravity = 9.80665 m/s²

#### Calculation

- 1 µHg Mass = 13595.1 kg/m³ x 1 m² x 0.000001 m = 0.0135951 kg
- 1 µHg Force = 0.0135951 kg x 9.80665 m/s² = 0.1333223874 N
- 1 µHg Pressure = 0.1333223874 N / 1 m² = 0.1333223874 Pa

**Low pressure measurement products**

- Minus 100 pascal suction pressure transmitter
- Minus 25 mb vacuum intrinsically safe 4-20mA pressure sensor
- G1/4 internal thread pressure transmitter for measuring 0-100mb
- 10Pa diff range 0-20mA output air pressure sensor for automotive component testing

## Alternate Descriptions

These are the different versions used for identifying mmHg that you may find elsewhere.

- Micron of Mercury
- Microns of Mercury
- Micrometre of Mercury
- Micrometer of Mercury
- Micron of Mercury Column
- Microns of Mercury Column
- Micrometre of Mercury Column
- Micrometer of Mercury Column
- µHg
- µ Hg
- µmHg
- µm Hg
- micron Hg
- micronHg

**Low pressure measurement products**

- 20 pascal differential pressure transducer for clean rooms
- Bidirectional -50 to +50 Pa diff pressure transmitter with user calibration adjustment
- Low Range Pressure Gauges
- Low vacuum leak detection 4-20mA current loop sensor & gauge