# Measurement.FormatStyle.ByteCount A format style that provides string representations of byte counts, expressed as measurements of information storage. ``` struct ByteCount ``` ## Overview Use this style with a [`Measurement`](/documentation/Foundation/Measurement) whose unit type is [`UnitInformationStorage`](/documentation/Foundation/UnitInformationStorage) to format byte counts according to locale conventions. The following example creates a measurement of 1,024 bytes, and then formats it as an expression of memory storage, with the default byte count format style: ```swift let count = Measurement(value: 1024, unit: UnitInformationStorage.bytes) let formatted = count.formatted(.byteCount(style: .memory)) // "1 kB" ``` You can also customize a byte count format style, and use this to format one or more [`Measurement`](/documentation/Foundation/Measurement) instances. The following example creates a format style to only use kilobyte units, and to spell out the exact byte count of the measurement. ```swift let count = Measurement(value: 1024, unit: UnitInformationStorage.bytes) let style = Measurement.FormatStyle.ByteCount(style: .memory, allowedUnits: .kb, spellsOutZero: true, includesActualByteCount: true, locale: Locale(identifier: "en_US")) let customFormatted = style.format(count) // "1 kB (1,024 bytes)" ``` ## Topics ### Creating a byte count style [`init(style: Measurement.FormatStyle.ByteCount.Style, allowedUnits: Measurement.FormatStyle.ByteCount.Units, spellsOutZero: Bool, includesActualByteCount: Bool, locale: Locale)`](/documentation/Foundation/Measurement/FormatStyle/ByteCount/init(style:allowedUnits:spellsOutZero:includesActualByteCount:locale:)) Initializes a byte count format style. ### Formatting byte count measurements [`func format(Measurement) -> String`](/documentation/Foundation/Measurement/FormatStyle/ByteCount/format(_:)) Formats a byte count measurment, using this style. ### Accessing style properties [`var allowedUnits: Measurement.FormatStyle.ByteCount.Units`](/documentation/Foundation/Measurement/FormatStyle/ByteCount/allowedUnits) The units the format style can use to express the byte count. [`typealias Units`](/documentation/Foundation/Measurement/FormatStyle/ByteCount/Units) The type the measurement format style uses to represent byte-counting units. [`var spellsOutZero: Bool`](/documentation/Foundation/Measurement/FormatStyle/ByteCount/spellsOutZero) A Boolean value that indicates whether the format style should spell out zero-byte values as text. [`var includesActualByteCount: Bool`](/documentation/Foundation/Measurement/FormatStyle/ByteCount/includesActualByteCount) A Boolean value that indicates whether the format style should include the exact byte count, in addition to expressing it in terms of units. [`var style: Measurement.FormatStyle.ByteCount.Style`](/documentation/Foundation/Measurement/FormatStyle/ByteCount/style-swift.property) The style of byte count to express, such as memory or file system storage. [`typealias Style`](/documentation/Foundation/Measurement/FormatStyle/ByteCount/Style-swift.typealias) The type used to represent the style of the formatted byte count. [`var locale: Locale`](/documentation/Foundation/Measurement/FormatStyle/ByteCount/locale) The locale to use to format the numeric part of the byte count. ### Modifying style locale [`func locale(Locale) -> Measurement.FormatStyle.ByteCount`](/documentation/Foundation/Measurement/FormatStyle/ByteCount/locale(_:)) Modifies the format style to use the specified locale. ### Applying currency styles ### Applying measurement styles ### Applying list styles ### Creating attributed strings [`var attributed: Measurement.AttributedStyle.ByteCount`](/documentation/Foundation/Measurement/FormatStyle/ByteCount/attributed) An attributed format style based on the byte count format style. [`struct ByteCount`](/documentation/Foundation/Measurement/AttributedStyle/ByteCount) A format style that converts byte counts into attributed strings. ### Supporting types ## Relationships ### Conforms To [`Sendable`](/documentation/Swift/Sendable) [`Equatable`](/documentation/Swift/Equatable) [`Decodable`](/documentation/Swift/Decodable) [`FormatStyle`](/documentation/Foundation/FormatStyle) [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`Hashable`](/documentation/Swift/Hashable) [`Encodable`](/documentation/Swift/Encodable) --- 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)