---
title: UnitPressure
framework: foundation
role: symbol
role_heading: Class
path: foundation/unitpressure
---

# UnitPressure

A unit of measure for pressure.

## Declaration

```swift
class UnitPressure
```

## Overview

Overview You typically use instances of UnitPressure to represent specific quantities of pressure using the NSMeasurement class. Pressure Pressure is the normal force over a surface. The SI unit for pressure is the pascal (Pa), which is derived as one newton of force over one square meter (1 Pa = 1 N / 1 m2). The UnitPressure class defines its baseUnit() as newtonsPerMetersSquared and provides the following units, which UnitConverterLinear converters initialize with the given coefficients:  |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |

## Topics

### Accessing the Base Unit

- [baseUnit()](foundation/dimension/baseunit().md)

### Accessing Predefined Units

- [gigapascals](foundation/unitpressure/gigapascals.md)
- [megapascals](foundation/unitpressure/megapascals.md)
- [kilopascals](foundation/unitpressure/kilopascals.md)
- [hectopascals](foundation/unitpressure/hectopascals.md)
- [inchesOfMercury](foundation/unitpressure/inchesofmercury.md)
- [bars](foundation/unitpressure/bars.md)
- [millibars](foundation/unitpressure/millibars.md)
- [millimetersOfMercury](foundation/unitpressure/millimetersofmercury.md)
- [newtonsPerMetersSquared](foundation/unitpressure/newtonspermeterssquared.md)
- [poundsForcePerSquareInch](foundation/unitpressure/poundsforcepersquareinch.md)

### Initializers

- [init(forLocale:usage:)](foundation/unitpressure/init(forlocale:usage:).md)

## Relationships

### Inherits From

- [Dimension](foundation/dimension.md)

### Conforms To

- [CVarArg](swift/cvararg.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [NSCoding](foundation/nscoding.md)
- [NSCopying](foundation/nscopying.md)
- [NSObjectProtocol](objectivec/nsobjectprotocol.md)
- [NSSecureCoding](foundation/nssecurecoding.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Mass, Weight, and Force

- [UnitMass](foundation/unitmass.md)