# Number Formatter Property Keys The keys used in key-value pairs to specify the value of number formatter properties. ## Discussion The values for these keys are all `CFType` objects. The specific types for each key are specified above. ## Topics ### Constants [`currencyCode`](/documentation/CoreFoundation/CFNumberFormatterKey/currencyCode) Specifies the currency code, a `CFString` object. [`decimalSeparator`](/documentation/CoreFoundation/CFNumberFormatterKey/decimalSeparator) Specifies the decimal separator, a `CFString` object. [`currencyDecimalSeparator`](/documentation/CoreFoundation/CFNumberFormatterKey/currencyDecimalSeparator) Specifies the currency decimal separator, a `CFString` object. [`alwaysShowDecimalSeparator`](/documentation/CoreFoundation/CFNumberFormatterKey/alwaysShowDecimalSeparator) Specifies if the result of converting a value to a string should always contain the decimal separator, even if the number is an integer. [`groupingSeparator`](/documentation/CoreFoundation/CFNumberFormatterKey/groupingSeparator) Specifies the grouping separator, a `CFString` object. [`useGroupingSeparator`](/documentation/CoreFoundation/CFNumberFormatterKey/useGroupingSeparator) Specifies if the grouping separator should be used, a `CFBoolean` object. [`percentSymbol`](/documentation/CoreFoundation/CFNumberFormatterKey/percentSymbol) Specifies the string that is used to represent the percent symbol, a `CFString` object. [`zeroSymbol`](/documentation/CoreFoundation/CFNumberFormatterKey/zeroSymbol) Specifies the string that is used to represent zero, a `CFString` object. [`naNSymbol`](/documentation/CoreFoundation/CFNumberFormatterKey/naNSymbol) Specifies the string that is used to represent NaN (“not a number”) when values are converted to strings, a `CFString` object. [`infinitySymbol`](/documentation/CoreFoundation/CFNumberFormatterKey/infinitySymbol) Specifies the string that is used to represent the symbol for infinity, a `CFString` object. [`minusSign`](/documentation/CoreFoundation/CFNumberFormatterKey/minusSign) Specifies the symbol for the minus sign, a `CFString` object. [`plusSign`](/documentation/CoreFoundation/CFNumberFormatterKey/plusSign) Specifies the symbol for the plus sign, a `CFString` object. [`currencySymbol`](/documentation/CoreFoundation/CFNumberFormatterKey/currencySymbol) Specifies the symbol for the currency, a `CFString` object. [`exponentSymbol`](/documentation/CoreFoundation/CFNumberFormatterKey/exponentSymbol) Specifies the exponent symbol (“E” or “e”) in the scientific notation of numbers (for example, as in `1.0e+56`), a `CFString` object. [`minIntegerDigits`](/documentation/CoreFoundation/CFNumberFormatterKey/minIntegerDigits) Specifies the minimum number of integer digits before a decimal point, a `CFNumber` object. [`maxIntegerDigits`](/documentation/CoreFoundation/CFNumberFormatterKey/maxIntegerDigits) Specifies the maximum number of integer digits before a decimal point, a `CFNumber` object. [`minFractionDigits`](/documentation/CoreFoundation/CFNumberFormatterKey/minFractionDigits) Specifies the minimum number of digits after a decimal point, a `CFNumber` object. [`maxFractionDigits`](/documentation/CoreFoundation/CFNumberFormatterKey/maxFractionDigits) Specifies the maximum number of digits after a decimal point, a `CFNumber` object. [`groupingSize`](/documentation/CoreFoundation/CFNumberFormatterKey/groupingSize) Specifies how often the “thousands” or grouping separator appears, as in “10,000,000”, a `CFNumber` object. [`secondaryGroupingSize`](/documentation/CoreFoundation/CFNumberFormatterKey/secondaryGroupingSize) Specifies how often the secondary grouping separator appears, a `CFNumber` object. [`roundingMode`](/documentation/CoreFoundation/CFNumberFormatterKey/roundingMode) Specifies how the last digit is rounded, as when `3.1415926535…` is rounded to three decimal places, as in `3.142`. See [`CFNumberFormatterRoundingMode`](/documentation/CoreFoundation/CFNumberFormatterRoundingMode) for possible values. [`roundingIncrement`](/documentation/CoreFoundation/CFNumberFormatterKey/roundingIncrement) Specifies a positive rounding increment, or `0.0` to disable rounding, a `CFNumber` object. [`formatWidth`](/documentation/CoreFoundation/CFNumberFormatterKey/formatWidth) Specifies the width of a formatted number within a string that is either left justified or right justified based on the value of [`paddingPosition`](/documentation/CoreFoundation/CFNumberFormatterKey/paddingPosition), a `CFNumber` object. [`paddingPosition`](/documentation/CoreFoundation/CFNumberFormatterKey/paddingPosition) Specifies the position of a formatted number within a string, a `CFNumber` object. [`paddingCharacter`](/documentation/CoreFoundation/CFNumberFormatterKey/paddingCharacter) Specifies the padding character to use when placing a formatted number within a string, a `CFString` object. [`defaultFormat`](/documentation/CoreFoundation/CFNumberFormatterKey/defaultFormat) The original format string for the formatter (given the date and time style and locale specified at creation), a `CFString` object. [`multiplier`](/documentation/CoreFoundation/CFNumberFormatterKey/multiplier) Specifies the multiplier to use when placing a formatted number within a string, a `CFNumber` object. [`positivePrefix`](/documentation/CoreFoundation/CFNumberFormatterKey/positivePrefix) Specifies the plus sign prefix symbol to use when placing a formatted number within a string, a `CFString` object. [`positiveSuffix`](/documentation/CoreFoundation/CFNumberFormatterKey/positiveSuffix) Specifies the plus sign suffix symbol to use when placing a formatted number within a string, a `CFString` object. [`negativePrefix`](/documentation/CoreFoundation/CFNumberFormatterKey/negativePrefix) Specifies the minus sign prefix symbol to use when placing a formatted number within a string, a `CFString` object. [`negativeSuffix`](/documentation/CoreFoundation/CFNumberFormatterKey/negativeSuffix) Specifies the minus sign suffix symbol to use when placing a formatted number within a string, a `CFString` object. [`perMillSymbol`](/documentation/CoreFoundation/CFNumberFormatterKey/perMillSymbol) Specifies the per mill (1/1000) symbol to use when placing a formatted number within a string, a `CFString` object. [`internationalCurrencySymbol`](/documentation/CoreFoundation/CFNumberFormatterKey/internationalCurrencySymbol) Specifies the international currency symbol to use when placing a formatted number within a string, a `CFString` object. [`currencyGroupingSeparator`](/documentation/CoreFoundation/CFNumberFormatterKey/currencyGroupingSeparator) Specifies the grouping symbol to use when placing a currency value within a string, a `CFString` object. [`isLenient`](/documentation/CoreFoundation/CFNumberFormatterKey/isLenient) Specifies whether the formatter is lenient, a`CFBoolean` object. [`useSignificantDigits`](/documentation/CoreFoundation/CFNumberFormatterKey/useSignificantDigits) Specifies the whether the formatter uses significant digits, a `CFBoolean` object. [`minSignificantDigits`](/documentation/CoreFoundation/CFNumberFormatterKey/minSignificantDigits) Specifies the minimum number of significant digits to use, a`CFNumber` object. [`maxSignificantDigits`](/documentation/CoreFoundation/CFNumberFormatterKey/maxSignificantDigits) Specifies the maximum number of significant digits to use, a`CFNumber` object. --- Copyright © 2026 Apple Inc. 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