---
title: millimeterOfMercury()
framework: healthkit
role: symbol
role_heading: Type Method
path: healthkit/hkunit/millimeterofmercury()
---

# millimeterOfMercury()

Returns a HealthKit unit for measuring pressure in millimeters of mercury.

## Declaration

```swift
class func millimeterOfMercury() -> Self
```

## Return Value

Return Value A HealthKit unit for measuring pressure in millimeters of mercury.

## Discussion

Discussion One millimeter of mercury is the pressure needed to raise a column of mercury by 1 millimeter. Even through it is not an SI unit, the millimeter of mercury unit is used in many scientific fields. In HealthKit, it is commonly used to measure blood pressure.

## See Also

### Constructing pressure units

- [pascal()](healthkit/hkunit/pascal().md)
- [pascalUnit(with:)](healthkit/hkunit/pascalunit(with:).md)
- [inchesOfMercury()](healthkit/hkunit/inchesofmercury().md)
- [centimeterOfWater()](healthkit/hkunit/centimeterofwater().md)
- [atmosphere()](healthkit/hkunit/atmosphere().md)
- [decibelAWeightedSoundPressureLevel()](healthkit/hkunit/decibelaweightedsoundpressurelevel().md)