---
title: UnitPower
framework: foundation
role: symbol
role_heading: Class
path: foundation/unitpower
---

# UnitPower

A unit of measure for power.

## Declaration

```swift
class UnitPower
```

## Overview

Overview You typically use instances of UnitPower to represent specific quantities of power using the NSMeasurement class. Power Power is the amount of energy used over time. The SI unit for power is the watt (W), which is derived as one joule per second (1W = 1J / 1s). The UnitPower class defines its baseUnit() as watts, and provides the following units, which are initialized using UnitConverterLinear converters with the specified coefficients:  |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |

## Topics

### Accessing the Base Unit

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

### Accessing Predefined Units

- [terawatts](foundation/unitpower/terawatts.md)
- [gigawatts](foundation/unitpower/gigawatts.md)
- [megawatts](foundation/unitpower/megawatts.md)
- [kilowatts](foundation/unitpower/kilowatts.md)
- [watts](foundation/unitpower/watts.md)
- [milliwatts](foundation/unitpower/milliwatts.md)
- [microwatts](foundation/unitpower/microwatts.md)
- [nanowatts](foundation/unitpower/nanowatts.md)
- [picowatts](foundation/unitpower/picowatts.md)
- [femtowatts](foundation/unitpower/femtowatts.md)
- [horsepower](foundation/unitpower/horsepower.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

### Energy, Heat, and Light

- [UnitEnergy](foundation/unitenergy.md)
- [UnitTemperature](foundation/unittemperature.md)
- [UnitIlluminance](foundation/unitilluminance.md)