# Custom Date/Time Format Strings

You can exercise greater control over how a DateTime object is formatted by using custom format specifiers to create your own custom format string. Combine one or more custom format specifiers to construct a formatting pattern that yields the output you prefer. In fact, most of the standard DateTime format specifiers are aliases for formatting patterns.

A custom pattern must be at least two characters long. If you pass only "d", it is interpreted as a standard format specifier because all single format specifiers are interpreted as standard. If you pass a single "h", an exception is thrown because there is not a standard "h" format specifier. To format using a single custom-defined format only, include a space before or after the specifier. For example, the format string "h " is interpreted as a custom-defined format string.

The following table describes the custom format specifiers and the results they produce. The output of these format specifiers is influenced by the current culture and the settings in the Regional Options control panel ((Control Panel - Regional and Language options - Regional Options - Advanced).

Format Specifier | Description
--- | ---
d | Displays the current day of the month, measured as a number between 1 and 31, inclusive. If the day is a single digit only (1-9), then it is displayed as a single digit. Note that if the 'd' format specifier is used alone, without other custom format strings, it is interpreted as the standard short date pattern format specifier. If the 'd' format specifier is passed with other custom format specifiers or the '%' character, it is interpreted as a custom format specifier.
dd | Displays the current day of the month, measured as a number between 1 and 31, inclusive. If the day is a single digit only (1-9), it is formatted with a preceding 0 (01-09).
ddd | Displays the abbreviated name of the day for the specified DateTime. If a specific valid format provider (a non-null object that implements IFormatProvider with the expected property) is not supplied, then the AbbreviatedDayNames property of the DateTimeFormat and its current culture associated with the current thread is used. Otherwise, the AbbreviatedDayNames property from the specified format provider is used.
dddd (plus any number of additional "d" characters) | Displays the full name of the day for the specified DateTime. If a specific valid format provider (a non-null object that implements IFormatProvider with the expected property) is not supplied, then the DayNames property of the DateTimeFormat and its current culture associated with the current thread is used. Otherwise, the DayNames property from the specified format provider is used.
f | Displays the most significant digit of the seconds fraction. Note that if the 'f' format specifier is used alone, without other custom format strings, it is interpreted as the full (long date + short time) format specifier. If the 'f' format specifier is passed with other custom format specifiers or the '%' character, it is interpreted as a custom format specifier. When you parse with the System.DateTime.ParseExact method, the number of 'f' format specifiers you use indicates the number of the most significant digits of the seconds fraction to parse.
ff | Displays the two most significant digits of the seconds fraction.
fff | Displays the three most significant digits of the seconds fraction.
ffff | Displays the four most significant digits of the seconds fraction.
fffff | Displays the five most significant digits of the seconds fraction.
ffffff | Displays the six most significant digits of the seconds fraction.
fffffff | Displays the seven most significant digits of the seconds fraction.
F | Displays the most significant digit of the seconds fraction. Nothing is displayed if the digit is zero. When you parse with the System.DateTime.ParseExact(System.String,System.String,System.IFormatProvider) method, the number of 'F' format specifiers you use indicates the maximum number of the most significant digits of the seconds fraction to parse.
FF | Displays the two most significant digits of the seconds fraction. However, trailing zeros, or two zero digits, are not displayed.
FFF | Displays the three most significant digits of the seconds fraction. However, trailing zeros, or three zero digits, are not displayed.
FFFF | Displays the four most significant digits of the seconds fraction. However, trailing zeros, or four zero digits, are not displayed.
FFFFF | Displays the five most significant digits of the seconds fraction. However, trailing zeros, or five zero digits, are not displayed.
FFFFFF | Displays the six most significant digits of the seconds fraction. However, trailing zeros, or six zero digits, are not displayed.
FFFFFFF | Displays the seven most significant digits of the seconds fraction. However, trailing zeros, or seven zero digits, are not displayed.
g or gg (plus any number of additional "g" characters) | Displays the era (A.D. for example) for the specified DateTime. If a specific valid format provider (a non-null object that implements IFormatProvider with the expected property) is not supplied, then the era is determined from the calendar associated with the DateTimeFormat and its current culture associated with the current thread. Note that if the 'g' format specifier is used alone, without other custom format strings, it is interpreted as the standard general format specifier. If the 'g' format specifier is passed with other custom format specifiers or the '%' character, it is interpreted as a custom format specifier.
h | Displays the hour for the specified DateTime in the range 1-12. The hour represents whole hours passed since either midnight (displayed as 12) or noon (also displayed as 12). If this format is used alone, then the same hour before or after noon is indistinguishable. If the hour is a single digit (1-9), it is displayed as a single digit. No rounding occurs when displaying the hour. For example, a DateTime of 5:43 returns 5.
hh, hh (plus any number of additional "h" characters) | Displays the hour for the specified DateTime in the range 1-12. The hour represents whole hours passed since either midnight (displayed as 12) or noon (also displayed as 12). If this format is used alone, then the same hour before or after noon is indistinguishable. If the hour is a single digit (1-9), it is formatted with a preceding 0 (01-09).
H | Displays the hour for the specified DateTime in the range 0-23. The hour represents whole hours passed since midnight (displayed as 0). If the hour is a single digit (0-9), it is displayed as a single digit.
HH, HH (plus any number of additional "H" characters) | Displays the hour for the specified DateTime in the range 0-23. The hour represents whole hours passed since midnight (displayed as 0). If the hour is a single digit (0-9), it is formatted with a preceding 0 (01-09).
m | Displays the minute for the specified DateTime in the range 0-59. The minute represents whole minutes passed since the last hour. If the minute is a single digit (0-9), it is displayed as a single digit. Note that if the 'm' format specifier is used alone, without other custom format strings, it is interpreted as the standard month day pattern format specifier. If the 'm' format specifier is passed with other custom format specifiers or the '%' character, it is interpreted as a custom format specifier.
mm, mm (plus any number of additional "m" characters) | Displays the minute for the specified DateTime in the range 0-59. The minute represents whole minutes passed since the last hour. If the minute is a single digit (0-9), it is formatted with a preceding 0 (01-09).
M | Displays the month, measured as a number between 1 and 12, inclusive. If the month is a single digit (1-9), it is displayed as a single digit. Note that if the 'M' format specifier is used alone, without other custom format strings, it is interpreted as the standard month day pattern format specifier. If the 'M' format specifier is passed with other custom format specifiers or the '%' character, it is interpreted as a custom format specifier.
MM | Displays the month, measured as a number between 1 and 12, inclusive. If the month is a single digit (1-9), it is formatted with a preceding 0 (01-09).
MMM | Displays the abbreviated name of the month for the specified DateTime. If a specific valid format provider (a non-null object that implements IFormatProvider with the expected property) is not supplied, the AbbreviatedMonthNames property of the DateTimeFormat and its current culture associated with the current thread is used. Otherwise, the AbbreviatedMonthNames property from the specified format provider is used.
MMMM | Displays the full name of the month for the specified DateTime. If a specific valid format provider (a non-null object that implements IFormatProvider with the expected property) is not supplied, then the MonthNames property of the DateTimeFormat and its current culture associated with the current thread is used. Otherwise, the MonthNames property from the specified format provider is used.
s | Displays the seconds for the specified DateTime in the range 0-59. The second represents whole seconds passed since the last minute. If the second is a single digit (0-9), it is displayed as a single digit only. Note that if the 's' format specifier is used alone, without other custom format strings, it is interpreted as the standard sortable date/time pattern format specifier. If the 's' format specifier is passed with other custom format specifiers or the '%' character, it is interpreted as a custom format specifier.
ss, ss (plus any number of additional "s" characters) | Displays the seconds for the specified DateTime in the range 0-59. The second represents whole seconds passed since the last minute. If the second is a single digit (0-9), it is formatted with a preceding 0 (01-09).
t | Displays the first character of the A.M./P.M. designator for the specified DateTime. If a specific valid format provider (a non-null object that implements IFormatProvider with the expected property) is not supplied, then the AMDesignator (or PMDesignator) property of the DateTimeFormat and its current culture associated with the current thread is used. Otherwise, the AMDesignator (or PMDesignator) property from the specified IFormatProvider is used. If the total number of whole hours passed for the specified DateTime is less than 12, then the AMDesignator is used. Otherwise, the PMDesignator is used. Note that if the 't' format specifier is used alone, without other custom format strings, it is interpreted as the standard long time pattern format specifier. If the 't' format specifier is passed with other custom format specifiers or the '%' character, it is interpreted as a custom format specifier.
tt, tt (plus any number of additional "t" characters) | Displays the A.M./P.M. designator for the specified DateTime. If a specific valid format provider (a non-null object that implements IFormatProvider with the expected property) is not supplied, then the AMDesignator (or PMDesignator) property of the DateTimeFormat and its current culture associated with the current thread is used. Otherwise, the AMDesignator (or PMDesignator) property from the specified IFormatProvider is used. If the total number of whole hours passed for the specified DateTime is less than 12, then the AMDesignator is used. Otherwise, the PMDesignator is used.
y | Displays the year for the specified DateTime as a maximum two-digit number. The first two digits of the year are omitted. If the year is a single digit (1-9), it is displayed as a single digit. Note that if the 'y' format specifier is used alone, without other custom format strings, it is interpreted as the standard short date pattern format specifier. If the 'y' format specifier is passed with other custom format specifiers or the '%' character, it is interpreted as a custom format specifier.
yy | Displays the year for the specified DateTime as a maximum two-digit number. The first two digits of the year are omitted. If the year is a single digit (1-9), it is formatted with a preceding 0 (01-09).
yyyy | Displays the year for the specified DateTime, including the century. If the year is less than four digits in length, then preceding zeros are appended as necessary to make the displayed year four digits long.
z | Displays the time zone offset for the system's current time zone in whole hours only. The offset is always displayed with a leading sign (zero is displayed as "+0"), indicating hours ahead of Greenwich mean time (+) or hours behind Greenwich mean time (-). The range of values is –12 to +13. If the offset is a single digit (0-9), it is displayed as a single digit with the appropriate leading sign. The setting for the time zone is specified as +X or –X where X is the offset in hours from GMT. The displayed offset is affected by daylight savings time.
zz | Displays the time zone offset for the system's current time zone in whole hours only. The offset is always displayed with a leading or trailing sign (zero is displayed as "+00"), indicating hours ahead of Greenwich mean time (+) or hours behind Greenwich mean time (-). The range of values is –12 to +13. If the offset is a single digit (0-9), it is formatted with a preceding 0 (01-09) with the appropriate leading sign. The setting for the time zone is specified as +X or –X where X is the offset in hours from GMT. The displayed offset is affected by daylight savings time.
zzz, zzz (plus any number of additional "z" characters) | Displays the time zone offset for the system's current time zone in hours and minutes. The offset is always displayed with a leading or trailing sign (zero is displayed as "+00:00"), indicating hours ahead of Greenwich mean time (+) or hours behind Greenwich mean time (-). The range of values is –12:00 to +13:00. If the offset is a single digit (0-9), it is formatted with a preceding 0 (01-09) with the appropriate leading sign. The setting for the time zone is specified as +X or –X where X is the offset in hours from GMT. The displayed offset is affected by daylight savings time.
: | Time separator.
/ | Date separator.
" | Quoted string. Displays the literal value of any string between two quotation marks preceded by the escape character (/).
' | Quoted string. Displays the literal value of any string between two " ' " characters.
%c | Where c is both a standard format specifier and a custom format specifier, displays the custom format pattern associated with the format specifier. Note that if a format specifier is used alone as a single character, it is interpreted as a standard format specifier. Only format specifiers consisting of two or more characters are interpreted as custom format specifiers. In order to display the custom format for a specifier defined as both a standard and a custom format specifier, precede the specifier with a % symbol.
\c | Where c is any character, the escape character displays the next character as a literal. The escape character cannot be used to create an escape sequence (like "\n" for new line) in this context.
Any other character | Other characters are written directly to the result string as literals.