# getMillisecondsInDuration()

Returns the number of milliseconds in a duration.

## Signature

`getMillisecondsInDuration(Duration duration)`

## Parameters

***duration*:** Type: `Duration`. The duration object returned by `$A.localizationService.duration`.

## Returns

**Type: `number`** The number of milliseconds in the duration.

**See Also**

- [duration()](/docs/platform/aura-platform/guide/ref-jsapi-auralocalizationservice-duration.md)