.NET Framework Developer's Guide

Standard DateTime Format Strings

A standard DateTime format string consists of a single format specifier character from the following table. If the format specifier is not found in the table below, a runtime exception is thrown. If the format string is longer than a single character (even if the extra characters are white spaces), the format string is interpreted as a custom format string.

Note that the result string produced by these format specifiers are influenced by the settings in the Regional Options control panel. Computers with different cultures or different date and time settings will generate different result strings.

The date and time separators displayed by format strings are defined by the DateSeparator and TimeSeparator characters associated with the DateTimeFormat property of the current culture. However, in cases where the InvariantCulture is referenced by the 'r', 's', and 'u' specifiers, the characters associated with the DateSeparator and TimeSeparator characters do not change based on the current culture.

The following table describes the standard format specifiers for formatting the DateTime object.

Format specifier	Name	Description
d	Short date pattern	Displays a pattern defined by the DateTimeFormatInfo.ShortDatePattern property associated with the current thread or by a specified format provider.
D	Long date pattern	Displays a pattern defined by the DateTimeFormatInfo.LongDatePattern property associated with the current thread or by a specified format provider.
t	Short time pattern	Displays a pattern defined by the DateTimeFormatInfo.ShortTimePattern property associated with the current thread or by a specified format provider.
T	Long time pattern	Displays a pattern defined by the DateTimeFormatInfo.LongTimePattern property associated with the current thread or by a specified format provider.
f	Full date/time pattern (short time)	Displays a combination of the long date and short time patterns, separated by a space.
F	Full date/time pattern (long time)	Displays a pattern defined by the DateTimeFormatInfo.FullDateTimePattern property associated with the current thread or by a specified format provider.
g	General date/time pattern (short time)	Displays a combination of the short date and short time patterns, separated by a space.
G	General date/time pattern (long time)	Displays a combination of the short date and long time patterns, separated by a space.
M or m	Month day pattern	Displays a pattern defined by the DateTimeFormatInfo.MonthDayPattern property associated with the current thread or by a specified format provider.
R or r	RFC1123 pattern	Displays a pattern defined by the DateTimeFormatInfo.RFC1123Pattern property associated with the current thread or by a specified format provider. This is a defined standard and the property is read-only; therefore, it is always the same regardless of the culture used, or the format provider supplied. The property references the CultureInfo.InvariantCulture property and follows the custom pattern "ddd, dd MMM yyyy HH:mm:ss G\MT". Note that the 'M' in "GMT" needs an escape character so it is not interpreted. Formatting does not modify the value of the DateTime; therefore, you must adjust the value to GMT before formatting.
s	Sortable date/time pattern; conforms to ISO 8601	Displays a pattern defined by the DateTimeFormatInfo.SortableDateTimePattern property associated with the current thread or by a specified format provider. The property references the CultureInfo.InvariantCulture property, and the format follows the custom pattern "yyyy-MM-ddTHH:mm:ss".
u	Universal sortable date/time pattern	Displays a pattern defined by the DateTimeFormatInfo.UniversalSortableDateTimePattern property associated with the current thread or by a specified format provider. Because it is a defined standard and the property is read-only, the pattern is always the same regardless of culture or format provider. Formatting follows the custom pattern "yyyy-MM-dd HH:mm:ssZ". No time zone conversion is done when the date and time is formatted; therefore, convert a local date and time to universal time before using this format specifier.
U	Universal sortable date/time pattern	Displays a pattern defined by the DateTimeFormatInfo.FullDateTimePattern property associated with the current thread or by a specified format provider. Note that the time displayed is for the universal, rather than local time.
Y or y	Year month pattern	Displays a pattern defined by the DateTimeFormatInfo.YearMonthPattern property associated with the current thread or by a specified format provider.
Any other single character	Unknown specifier

The following example illustrates how to use the standard format strings with DateTime objects.

[Visual Basic]Dim dt As DateTime = DateTime.NowDim dfi As DateTimeFormatInfo = New DateTimeFormatInfo()Dim ci As CultureInfo = New CultureInfo("de-DE")' Make up a new custom DateTime pattern, for demonstration.dfi.MonthDayPattern = "MM-MMMM, ddd-dddd"' Use the DateTimeFormat from the culture associated ' with the current thread.Console.WriteLine( dt.ToString("d") )  Console.WriteLine( dt.ToString("m") )' Use the DateTimeFormat from the specific culture passed.Console.WriteLine( dt.ToString("d", ci ) )' Use the settings from the DateTimeFormatInfo object passed.Console.WriteLine( dt.ToString("m", dfi ) )' Reset the current thread to a different culture.Thread.CurrentThread.CurrentCulture = New CultureInfo("fr-BE")Console.WriteLine( dt.ToString("d") )[C#]DateTime dt = DateTime.Now;DateTimeFormatInfo dfi = new DateTimeFormatInfo();CultureInfo ci = new CultureInfo("de-DE");// Make up a new custom DateTime pattern, for demonstration.dfi.MonthDayPattern = "MM-MMMM, ddd-dddd";// Use the DateTimeFormat from the culture associated // with the current thread.Console.WriteLine( dt.ToString("d") );  Console.WriteLine( dt.ToString("m") );// Use the DateTimeFormat from the specific culture passed.Console.WriteLine( dt.ToString("d", ci ) );// Use the settings from the DateTimeFormatInfo object passed.Console.WriteLine( dt.ToString("m", dfi ) );// Reset the current thread to a different culture.Thread.CurrentThread.CurrentCulture = new CultureInfo("fr-BE");Console.WriteLine( dt.ToString("d") );