# units(allowed:width:maximumUnitCount:zeroValueUnits:valueLength:fractionalPart:) Returns a style for formatting a duration that uses the specified units. ``` static func units(allowed units: Set = [.hours, .minutes, .seconds], width: Duration.UnitsFormatStyle.UnitWidth = .abbreviated, maximumUnitCount: Int? = nil, zeroValueUnits: Duration.UnitsFormatStyle.ZeroValueUnitsDisplayStrategy = .hide, valueLength: Int? = nil, fractionalPart: Duration.UnitsFormatStyle.FractionalPartDisplayStrategy = .hide) -> Self ``` ## Parameters `units` The units that the formatted string may include. `width` The width of the unit and the spacing between the value and the unit. `maximumUnitCount` The maximum number of duration units, if any, to include in the output string. `zeroValueUnits` The strategy for handling leading units with zero values. `valueLength` The padding or truncating behavior of the unit value, as an `Int`. Defaults to `nil`, which applies no length limit. `fractionalPart` The strategy for displaying a duration if a formatted string can’t represent it exactly with the allowed units. ## Return Value A duration units format style that uses the specified units. ## Discussion Use the dot-notation form of this type method when the call point allows the use of . You typically do this when calling the method of . The following example creates a duration to represent 1 hour, 10 minutes, 32 seconds, and 400 milliseconds. It then creates a to show the hours, minutes, seconds, and milliseconds parts, with a wide width that presents the full name of each unit. ```swift let duration = Duration.seconds(70 * 60 + 32) + Duration.milliseconds(400) let formatted = duration.formatted( .units(allowed: [.hours, .minutes, .seconds, .milliseconds], width: .wide)) // "1 hour, 10 minutes, 32 seconds, 400 milliseconds" ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)