Standard date and time format strings

บทความ
05/02/2023

A standard date and time format string uses a single character as the format specifier to define the text representation of a DateTime or a DateTimeOffset value. Any date and time format string that contains more than one character, including white space, is interpreted as a custom date and time format string. A standard or custom format string can be used in two ways:

To define the string that results from a formatting operation.
To define the text representation of a date and time value that can be converted to a DateTime or DateTimeOffset value by a parsing operation.

Tip

You can download the Formatting Utility, a .NET Windows Forms application that lets you apply format strings to either numeric or date and time values and display the result string. Source code is available for C# and Visual Basic.

Note

Some of the C# examples in this article run in the Try.NET inline code runner and playground. Select the Run button to run an example in an interactive window. Once you execute the code, you can modify it and run the modified code by selecting Run again. The modified code either runs in the interactive window or, if compilation fails, the interactive window displays all C# compiler error messages.

The local time zone of the Try.NET inline code runner and playground is Coordinated Universal Time, or UTC. This may affect the behavior and the output of examples that illustrate the DateTime, DateTimeOffset, and TimeZoneInfo types and their members.

Table of format specifiers

The following table describes the standard date and time format specifiers. Unless otherwise noted, a particular standard date and time format specifier produces an identical string representation regardless of whether it is used with a DateTime or a DateTimeOffset value. See Control Panel Settings and DateTimeFormatInfo Properties for additional information about using standard date and time format strings.

Format specifier	Description	Examples
"d"	Short date pattern. More information:The short date ("d") format specifier.	2009-06-15T13:45:30 -> 6/15/2009 (en-US) 2009-06-15T13:45:30 -> 15/06/2009 (fr-FR) 2009-06-15T13:45:30 -> 2009/06/15 (ja-JP)
"D"	Long date pattern. More information:The long date ("D") format specifier.	2009-06-15T13:45:30 -> Monday, June 15, 2009 (en-US) 2009-06-15T13:45:30 -> понедельник, 15 июня 2009 г. (ru-RU) 2009-06-15T13:45:30 -> Montag, 15. Juni 2009 (de-DE)
"f"	Full date/time pattern (short time). More information: The full date short time ("f") format specifier.	2009-06-15T13:45:30 -> Monday, June 15, 2009 1:45 PM (en-US) 2009-06-15T13:45:30 -> den 15 juni 2009 13:45 (sv-SE) 2009-06-15T13:45:30 -> Δευτέρα, 15 Ιουνίου 2009 1:45 μμ (el-GR)
"F"	Full date/time pattern (long time). More information: The full date long time ("F") format specifier.	2009-06-15T13:45:30 -> Monday, June 15, 2009 1:45:30 PM (en-US) 2009-06-15T13:45:30 -> den 15 juni 2009 13:45:30 (sv-SE) 2009-06-15T13:45:30 -> Δευτέρα, 15 Ιουνίου 2009 1:45:30 μμ (el-GR)
"g"	General date/time pattern (short time). More information: The general date short time ("g") format specifier.	2009-06-15T13:45:30 -> 6/15/2009 1:45 PM (en-US) 2009-06-15T13:45:30 -> 15/06/2009 13:45 (es-ES) 2009-06-15T13:45:30 -> 2009/6/15 13:45 (zh-CN)
"G"	General date/time pattern (long time). More information: The general date long time ("G") format specifier.	2009-06-15T13:45:30 -> 6/15/2009 1:45:30 PM (en-US) 2009-06-15T13:45:30 -> 15/06/2009 13:45:30 (es-ES) 2009-06-15T13:45:30 -> 2009/6/15 13:45:30 (zh-CN)
"M", "m"	Month/day pattern. More information: The month ("M", "m") format specifier.	2009-06-15T13:45:30 -> June 15 (en-US) 2009-06-15T13:45:30 -> 15. juni (da-DK) 2009-06-15T13:45:30 -> 15 Juni (id-ID)
"O", "o"	round-trip date/time pattern. More information: The round-trip ("O", "o") format specifier.	DateTime values: 2009-06-15T13:45:30 (DateTimeKind.Local) --> 2009-06-15T13:45:30.0000000-07:00 2009-06-15T13:45:30 (DateTimeKind.Utc) --> 2009-06-15T13:45:30.0000000Z 2009-06-15T13:45:30 (DateTimeKind.Unspecified) --> 2009-06-15T13:45:30.0000000 DateTimeOffset values: 2009-06-15T13:45:30-07:00 --> 2009-06-15T13:45:30.0000000-07:00
"R", "r"	RFC1123 pattern. More information: The RFC1123 ("R", "r") format specifier.	DateTimeOffset input: 2009-06-15T13:45:30 -> Mon, 15 Jun 2009 20:45:30 GMT DateTime input: 2009-06-15T13:45:30 -> Mon, 15 Jun 2009 13:45:30 GMT
"s"	Sortable date/time pattern. More information: The sortable ("s") format specifier.	2009-06-15T13:45:30 (DateTimeKind.Local) -> 2009-06-15T13:45:30 2009-06-15T13:45:30 (DateTimeKind.Utc) -> 2009-06-15T13:45:30
"t"	Short time pattern. More information: The short time ("t") format specifier.	2009-06-15T13:45:30 -> 1:45 PM (en-US) 2009-06-15T13:45:30 -> 13:45 (hr-HR) 2009-06-15T13:45:30 -> 01:45 م (ar-EG)
"T"	Long time pattern. More information: The long time ("T") format specifier.	2009-06-15T13:45:30 -> 1:45:30 PM (en-US) 2009-06-15T13:45:30 -> 13:45:30 (hr-HR) 2009-06-15T13:45:30 -> 01:45:30 م (ar-EG)
"u"	Universal sortable date/time pattern. More information: The universal sortable ("u") format specifier.	With a DateTime value: 2009-06-15T13:45:30 -> 2009-06-15 13:45:30Z With a DateTimeOffset value: 2009-06-15T13:45:30 -> 2009-06-15 20:45:30Z
"U"	Universal full date/time pattern. More information: The universal full ("U") format specifier.	2009-06-15T13:45:30 -> Monday, June 15, 2009 8:45:30 PM (en-US) 2009-06-15T13:45:30 -> den 15 juni 2009 20:45:30 (sv-SE) 2009-06-15T13:45:30 -> Δευτέρα, 15 Ιουνίου 2009 8:45:30 μμ (el-GR)
"Y", "y"	Year month pattern. More information: The year month ("Y") format specifier.	2009-06-15T13:45:30 -> June 2009 (en-US) 2009-06-15T13:45:30 -> juni 2009 (da-DK) 2009-06-15T13:45:30 -> Juni 2009 (id-ID)
Any other single character	Unknown specifier.	Throws a run-time FormatException.

How standard format strings work

In a formatting operation, a standard format string is simply an alias for a custom format string. The advantage of using an alias to refer to a custom format string is that, although the alias remains invariant, the custom format string itself can vary. This is important because the string representations of date and time values typically vary by culture. For example, the "d" standard format string indicates that a date and time value is to be displayed using a short date pattern. For the invariant culture, this pattern is "MM/dd/yyyy". For the fr-FR culture, it is "dd/MM/yyyy". For the ja-JP culture, it is "yyyy/MM/dd".

If a standard format string in a formatting operation maps to a particular culture's custom format string, your application can define the specific culture whose custom format strings are used in one of these ways:

You can use the default (or current) culture. The following example displays a date using the current culture's short date format. In this case, the current culture is en-US.

// Display using current (en-us) culture's short date format
DateTime thisDate = new DateTime(2008, 3, 15);
Console.WriteLine(thisDate.ToString("d"));           // Displays 3/15/2008

' Display using current (en-us) culture's short date format
Dim thisDate As Date = #03/15/2008#
Console.WriteLine(thisDate.ToString("d"))     ' Displays 3/15/2008

You can pass a CultureInfo object representing the culture whose formatting is to be used to a method that has an IFormatProvider parameter. The following example displays a date using the short date format of the pt-BR culture.

// Display using pt-BR culture's short date format
DateTime thisDate = new DateTime(2008, 3, 15);
CultureInfo culture = new CultureInfo("pt-BR");
Console.WriteLine(thisDate.ToString("d", culture));  // Displays 15/3/2008

' Display using pt-BR culture's short date format
Dim thisDate As Date = #03/15/2008#
Dim culture As New CultureInfo("pt-BR")
Console.WriteLine(thisDate.ToString("d", culture))   ' Displays 15/3/2008

You can pass a DateTimeFormatInfo object that provides formatting information to a method that has an IFormatProvider parameter. The following example displays a date using the short date format from a DateTimeFormatInfo object for the hr-HR culture.

// Display using date format information from hr-HR culture
DateTime thisDate = new DateTime(2008, 3, 15);
DateTimeFormatInfo fmt = (new CultureInfo("hr-HR")).DateTimeFormat;
Console.WriteLine(thisDate.ToString("d", fmt));      // Displays 15.3.2008

' Display using date format information from hr-HR culture
Dim thisDate As Date = #03/15/2008#
Dim fmt As DateTimeFormatInfo = (New CultureInfo("hr-HR")).DateTimeFormat
Console.WriteLine(thisDate.ToString("d", fmt))   ' Displays 15.3.2008

Note

For information about customizing the patterns or strings used in formatting date and time values, see the NumberFormatInfo class topic.

In some cases, the standard format string serves as a convenient abbreviation for a longer custom format string that is invariant. Four standard format strings fall into this category: "O" (or "o"), "R" (or "r"), "s", and "u". These strings correspond to custom format strings defined by the invariant culture. They produce string representations of date and time values that are intended to be identical across cultures. The following table provides information on these four standard date and time format strings.

Standard format string	Defined by DateTimeFormatInfo.InvariantInfo property	Custom format string
"O" or "o"	None	yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffffffK
"R" or "r"	RFC1123Pattern	ddd, dd MMM yyyy HH':'mm':'ss 'GMT'
"s"	SortableDateTimePattern	yyyy'-'MM'-'dd'T'HH':'mm':'ss
"u"	UniversalSortableDateTimePattern	yyyy'-'MM'-'dd HH':'mm':'ss'Z'

Standard format strings can also be used in parsing operations with the DateTime.ParseExact or DateTimeOffset.ParseExact methods, which require an input string to exactly conform to a particular pattern for the parse operation to succeed. Many standard format strings map to multiple custom format strings, so a date and time value can be represented in a variety of formats and the parse operation will still succeed. You can determine the custom format string or strings that correspond to a standard format string by calling the DateTimeFormatInfo.GetAllDateTimePatterns(Char) method. The following example displays the custom format strings that map to the "d" (short date pattern) standard format string.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      Console.WriteLine("'d' standard format string:");
      foreach (var customString in DateTimeFormatInfo.CurrentInfo.GetAllDateTimePatterns('d'))
          Console.WriteLine("   {0}", customString);
   }
}
// The example displays the following output:
//       'd' standard format string:
//          M/d/yyyy
//          M/d/yy
//          MM/dd/yy
//          MM/dd/yyyy
//          yy/MM/dd
//          yyyy-MM-dd
//          dd-MMM-yy

Imports System.Globalization

Module Example
    Public Sub Main()
        Console.WriteLine("'d' standard format string:")
        For Each customString In DateTimeFormatInfo.CurrentInfo.GetAllDateTimePatterns("d"c)
            Console.WriteLine("   {0}", customString)
        Next
    End Sub
End Module
' The example displays the following output:
'    'd' standard format string:
'       M/d/yyyy
'       M/d/yy
'       MM/dd/yy
'       MM/dd/yyyy
'       yy/MM/dd
'       yyyy-MM-dd
'       dd-MMM-yy

The following sections describe the standard format specifiers for DateTime and DateTimeOffset values.

Date formats

This group includes the following formats:

The short date ("d") format specifier
The long date ("D") format specifier

The short date ("d") format specifier

The "d" standard format specifier represents a custom date and time format string that is defined by a specific culture's DateTimeFormatInfo.ShortDatePattern property. For example, the custom format string that is returned by the ShortDatePattern property of the invariant culture is "MM/dd/yyyy".

The following table lists the DateTimeFormatInfo object properties that control the formatting of the returned string.

Property	Description
ShortDatePattern	Defines the overall format of the result string.
DateSeparator	Defines the string that separates the year, month, and day components of a date.

The following example uses the "d" format specifier to display a date and time value.

DateTime date1 = new DateTime(2008,4, 10);
Console.WriteLine(date1.ToString("d", DateTimeFormatInfo.InvariantInfo));
// Displays 04/10/2008
Console.WriteLine(date1.ToString("d",
                  CultureInfo.CreateSpecificCulture("en-US")));
// Displays 4/10/2008
Console.WriteLine(date1.ToString("d",
                  CultureInfo.CreateSpecificCulture("en-NZ")));
// Displays 10/04/2008
Console.WriteLine(date1.ToString("d",
                  CultureInfo.CreateSpecificCulture("de-DE")));
// Displays 10.04.2008

Dim date1 As Date = #4/10/2008#
Console.WriteLine(date1.ToString("d", DateTimeFormatInfo.InvariantInfo))
' Displays 04/10/2008
Console.WriteLine(date1.ToString("d", _
                  CultureInfo.CreateSpecificCulture("en-US")))
' Displays 4/10/2008                       
Console.WriteLine(date1.ToString("d", _
                  CultureInfo.CreateSpecificCulture("en-NZ")))
' Displays 10/04/2008                       
Console.WriteLine(date1.ToString("d", _
                  CultureInfo.CreateSpecificCulture("de-DE")))
' Displays 10.04.2008

Property	Description
LongDatePattern	Defines the overall format of the result string.
DayNames	Defines the localized day names that can appear in the result string.
MonthNames	Defines the localized month names that can appear in the result string.

Property	Description
LongDatePattern	Defines the format of the date component of the result string.
ShortTimePattern	Defines the format of the time component of the result string.
DayNames	Defines the localized day names that can appear in the result string.
MonthNames	Defines the localized month names that can appear in the result string.
TimeSeparator	Defines the string that separates the hour, minute, and second components of a time.
AMDesignator	Defines the string that indicates times from midnight to before noon in a 12-hour clock.
PMDesignator	Defines the string that indicates times from noon to before midnight in a 12-hour clock.

Property	Description
FullDateTimePattern	Defines the overall format of the result string.
DayNames	Defines the localized day names that can appear in the result string.
MonthNames	Defines the localized month names that can appear in the result string.
TimeSeparator	Defines the string that separates the hour, minute, and second components of a time.
AMDesignator	Defines the string that indicates times from midnight to before noon in a 12-hour clock.
PMDesignator	Defines the string that indicates times from noon to before midnight in a 12-hour clock.

Property	Description
ShortDatePattern	Defines the format of the date component of the result string.
LongTimePattern	Defines the format of the time component of the result string.
DateSeparator	Defines the string that separates the year, month, and day components of a date.
TimeSeparator	Defines the string that separates the hour, minute, and second components of a time.
AMDesignator	Defines the string that indicates times from midnight to before noon in a 12-hour clock.
PMDesignator	Defines the string that indicates times from noon to before midnight in a 12-hour clock.

Property	Description
RFC1123Pattern	Defines the format of the result string.
AbbreviatedDayNames	Defines the abbreviated day names that can appear in the result string.
AbbreviatedMonthNames	Defines the abbreviated month names that can appear in the result string.

Property	Description
MonthDayPattern	Defines the overall format of the result string.
MonthNames	Defines the localized month names that can appear in the result string.

Property	Description
YearMonthPattern	Defines the overall format of the result string.
MonthNames	Defines the localized month names that can appear in the result string.

แชร์ผ่าน

Standard date and time format strings

Table of format specifiers

How standard format strings work

Date formats

The short date ("d") format specifier

The long date ("D") format specifier

Date and time formats

The full date short time ("f") format specifier

The full date long time ("F") format specifier

The general date short time ("g") format specifier

The general date long time ("G") format specifier

The round-trip ("O", "o") format specifier

The RFC1123 ("R", "r") format specifier

The sortable ("s") format specifier

The universal sortable ("u") format specifier

The universal full ("U") format specifier

Time formats

The short time ("t") format specifier

The long time ("T") format specifier

Partial date formats

The month ("M", "m") format specifier

The year month ("Y", "y") format specifier

Control Panel settings

DateTimeFormatInfo properties

See also

แหล่งทรัพยากรเพิ่มเติม