# CFNumberFormatter ``` class CFNumberFormatter ``` ## Overview CFNumberFormatter objects format the textual representations of CFNumber objects, and convert textual representations of numbers into CFNumber objects. The representation encompasses integers, floats, and doubles; floats and doubles can be formatted to a specified decimal position. You specify how strings are formatted and parsed by setting a format string and other properties of a CFNumberFormatter object. The format of the format string is defined by Unicode Technical Standard #35; the version of the standard used varies with release of the operating system, and is described in [Introduction to Data Formatting Programming Guide For Cocoa](https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/DataFormatting/DataFormatting.html#//apple_ref/doc/uid/10000029). > Important: > `CFNumberFormatter` is not thread-safe. Do not use a single instance from multiple threads. Unlike some other Core Foundation opaque types with names similar to a corresponding Cocoa Foundation class (such as CFString and `NSString`), CFNumberFormatter objects cannot be cast (“toll-free bridged”) to `NSNumberFormatter` objects. ## Topics ### Creating a Number Formatter [`CFNumberFormatterCreate(_:_:_:)`](/documentation/CoreFoundation/CFNumberFormatterCreate(_:_:_:)) Creates a new CFNumberFormatter object, localized to the given locale, which will format numbers to the given style. ### Configuring a Number Formatter [`CFNumberFormatterSetFormat(_:_:)`](/documentation/CoreFoundation/CFNumberFormatterSetFormat(_:_:)) Sets the format string of a number formatter. [`CFNumberFormatterSetProperty(_:_:_:)`](/documentation/CoreFoundation/CFNumberFormatterSetProperty(_:_:_:)) Sets a number formatter property using a key-value pair. ### Formatting Values [`CFNumberFormatterCreateNumberFromString(_:_:_:_:_:)`](/documentation/CoreFoundation/CFNumberFormatterCreateNumberFromString(_:_:_:_:_:)) Returns a number object representing a given string. [`CFNumberFormatterCreateStringWithNumber(_:_:_:)`](/documentation/CoreFoundation/CFNumberFormatterCreateStringWithNumber(_:_:_:)) Returns a string representation of the given number using the specified number formatter. [`CFNumberFormatterCreateStringWithValue(_:_:_:_:)`](/documentation/CoreFoundation/CFNumberFormatterCreateStringWithValue(_:_:_:_:)) Returns a string representation of the given number or value using the specified number formatter. [`CFNumberFormatterGetDecimalInfoForCurrencyCode(_:_:_:)`](/documentation/CoreFoundation/CFNumberFormatterGetDecimalInfoForCurrencyCode(_:_:_:)) Returns the number of fraction digits that should be displayed, and the rounding increment, for a given currency. [`CFNumberFormatterGetValueFromString(_:_:_:_:_:)`](/documentation/CoreFoundation/CFNumberFormatterGetValueFromString(_:_:_:_:_:)) Returns a number or value representing a given string. ### Examining a Number Formatter [`CFNumberFormatterCopyProperty(_:_:)`](/documentation/CoreFoundation/CFNumberFormatterCopyProperty(_:_:)) Returns a copy of a number formatter’s value for a given key. [`CFNumberFormatterGetFormat(_:)`](/documentation/CoreFoundation/CFNumberFormatterGetFormat(_:)) Returns a format string for the given number formatter object. [`CFNumberFormatterGetLocale(_:)`](/documentation/CoreFoundation/CFNumberFormatterGetLocale(_:)) Returns the locale object used to create the given number formatter object. [`CFNumberFormatterGetStyle(_:)`](/documentation/CoreFoundation/CFNumberFormatterGetStyle(_:)) Returns the number style used to create the given number formatter object. ### Getting the CFNumberFormatter Type ID [`CFNumberFormatterGetTypeID()`](/documentation/CoreFoundation/CFNumberFormatterGetTypeID()) Returns the type identifier for the `CFNumberFormatter` opaque type. ### Data Types [`CFNumberFormatterStyle`](/documentation/CoreFoundation/CFNumberFormatterStyle) Type for constants specifying a formatter style. [`CFNumberFormatterOptionFlags`](/documentation/CoreFoundation/CFNumberFormatterOptionFlags) Type for constants specifying how numbers should be parsed. [`CFNumberFormatterPadPosition`](/documentation/CoreFoundation/CFNumberFormatterPadPosition) Type for constants specifying how numbers should be padded. ### Constants [Number Formatter Styles](/documentation/CoreFoundation/number-formatter-styles) Predefined number format styles. [Number Formatter Property Keys](/documentation/CoreFoundation/number-formatter-property-keys) The keys used in key-value pairs to specify the value of number formatter properties. [Number Format Options](/documentation/CoreFoundation/number_format_options) These constants are used to specify how numbers should be parsed. [`CFNumberFormatterRoundingMode`](/documentation/CoreFoundation/CFNumberFormatterRoundingMode) These constants are used to specify how numbers should be rounded. [Padding Positions](/documentation/CoreFoundation/padding-positions) These constants are used to specify how numbers should be padded. ## See Also [Data Formatting Guide for Core Foundation](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFDataFormatting/Articles/CFDataFormatting.html#//apple_ref/doc/uid/10000176i) --- Copyright © 2026 Apple Inc. 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