Bytes Count Formatting

Value in bytes can be converted into localized human-readable form by using ByteCountFormatter:

ByteCountFormatter.string(fromByteCount: 12345678, countStyle: .file) // '12.3 MB'

If more options need to be configured, instantiate ByteCountFormatter:

let formatter = ByteCountFormatter()
formatter.allowedUnits = .useAll
formatter.countStyle = .file
formatter.includesUnit = true
formatter.isAdaptive = true

formatter.string(fromByteCount: 123456789000) // '123.46 GB'
formatter.string(fromByteCount: 0) // 'Zero KB'

The formatter will automatically pick the most suitable measurement unit, since we specified useAll option. It can be forced to use one or more pre-defined units.

By setting isAdaptive to true, we instructed the formatter to automatically pick the number of fraction digits based on the magnitude, e.g. 1 digit for megabytes, 2 for gigabytes and above.

Further reading

• Apple docs on ByteCountFormatter
• Formatter’s source code from Swift repository