C# DateTime format

last modified October 5, 2026

In this article we learn how to format DateTime values in C# using standard and custom date and time format strings.

C# DateTime

The DateTime value type represents dates and times with values ranging from 00:00:00 (midnight), January 1, 0001, through 11:59:59 PM, December 31, 9999, in the Gregorian calendar. It does not include a time zone; use DateTimeOffset when an offset is part of the value.

Format methods

To format a DateTime value, we can use DateTime.ToString, String.Format, or an interpolated string such as $"{date:D}". The result depends on the current culture unless a specific CultureInfo is supplied.

C# standard format specifiers

A standard datetime format string uses a single character format specifier to define the text representation of a DateTime value. For instance, the D format specifier denotes a long date format.

Specifier	Meaning	Example (en-US culture)
D	long date	Saturday, March 26, 2022
d	short date	03/26/2022
F	full date and long time	Saturday, March 26, 2022 1:15:12 PM
f	full date and short time	Saturday, March 26, 2022 1:15 PM
G	general date and long time	03/26/2022 1:15:12 PM
g	general date and short time	03/26/2022 1:15 PM
U	universal full date and time	Saturday, March 26, 2022 1:15:12 PM
u	universal sortable date and time	2022-03-26 13:15:12Z
s	sortable date and time	2022-03-26T13:15:12
T	long time	1:15:12 PM
t	short time	1:15 PM
O	round-trip date and time	2022-03-26T13:15:12.6720000Z
R	RFC 1123 date and time	Sat, 26 Mar 2022 13:15:12 GMT
M	month and day	March 26
Y	year and month	March 2022

The table lists standard datetime format specifiers in C#.

using System.Globalization;

var date = new DateTime(2022, 3, 26, 13, 15, 12, 672, DateTimeKind.Utc);
var culture = CultureInfo.GetCultureInfo("en-US");

Console.WriteLine(date.ToString("D", culture));
Console.WriteLine(date.ToString("d", culture));
Console.WriteLine(date.ToString("F", culture));
Console.WriteLine(date.ToString("f", culture));
Console.WriteLine(date.ToString("G", culture));
Console.WriteLine(date.ToString("g", culture));
Console.WriteLine(date.ToString("U", culture));
Console.WriteLine(date.ToString("u", culture));
Console.WriteLine(date.ToString("s", culture));
Console.WriteLine(date.ToString("T", culture));
Console.WriteLine(date.ToString("t", culture));
Console.WriteLine(date.ToString("O", culture));
Console.WriteLine(date.ToString("R", culture));
Console.WriteLine(date.ToString("M", culture));
Console.WriteLine(date.ToString("Y", culture));

In the example, we use standard date and time format specifiers with a fixed UTC value and the en-US culture. The U and u formats convert a DateTime value to UTC before formatting it.

$ dotnet run
Saturday, March 26, 2022
03/26/2022
Saturday, March 26, 2022 1:15:12 PM
Saturday, March 26, 2022 1:15 PM
03/26/2022 1:15:12 PM
03/26/2022 1:15 PM
Saturday, March 26, 2022 1:15:12 PM
2022-03-26 13:15:12Z
2022-03-26T13:15:12
1:15:12 PM
1:15 PM
2022-03-26T13:15:12.6720000Z
Sat, 26 Mar 2022 13:15:12 GMT
March 26
March 2022

---

using System.Globalization;

var date = new DateTime(2022, 3, 26, 13, 15, 12, 672, DateTimeKind.Utc);

Console.WriteLine(FormattableString.Invariant($"{date:D}"));
Console.WriteLine(FormattableString.Invariant($"{date:O}"));
Console.WriteLine(FormattableString.Invariant($"{date:R}"));

Interpolated strings can also contain standard format specifiers. FormattableString.Invariant makes the culture explicit for these examples; ordinary interpolated strings use the current culture.

C# culture-specific standard format specifiers

Pass a CultureInfo to a formatting method when the output must follow a particular culture. This avoids changing the process-wide current culture.

using System.Globalization;

var date = new DateTime(2022, 3, 26, 13, 15, 12, 672, DateTimeKind.Utc);
var culture = CultureInfo.GetCultureInfo("sk-SK");

Console.WriteLine(date.ToString("D", culture));
Console.WriteLine(date.ToString("d", culture));
Console.WriteLine(date.ToString("F", culture));
Console.WriteLine(date.ToString("f", culture));
Console.WriteLine(date.ToString("G", culture));
Console.WriteLine(date.ToString("g", culture));
Console.WriteLine(date.ToString("U", culture));
Console.WriteLine(date.ToString("u", culture));
Console.WriteLine(date.ToString("s", culture));
Console.WriteLine(date.ToString("T", culture));
Console.WriteLine(date.ToString("t", culture));
Console.WriteLine(date.ToString("O", culture));
Console.WriteLine(date.ToString("R", culture));
Console.WriteLine(date.ToString("M", culture));
Console.WriteLine(date.ToString("Y", culture));

In the example, we format the same UTC value with standard specifiers for the Slovak culture. Numeric and textual components follow that culture where the format permits them; invariant formats such as O and R retain their defined layout.

$ dotnet run
sobota 26. marca 2022
26. 3. 2022
sobota 26. marca 2022 13:15:12
sobota 26. marca 2022 13:15
26. 3. 2022 13:15:12
26. 3. 2022 13:15
sobota 26. marca 2022 13:15:12
2022-03-26 13:15:12Z
2022-03-26T13:15:12
13:15:12
13:15
2022-03-26T13:15:12.6720000Z
Sat, 26 Mar 2022 13:15:12 GMT
26. marca
marec 2022

C# custom datetime format specifiers

Custom date and time format specifiers are combined to build a format that is not covered by a standard format string. A format string containing a single custom letter must be escaped or quoted when it could be interpreted as a standard format specifier.

Specifier	Meaning
d	The day of the month, from 1 through 31.
dd	The day of the month, from 01 through 31.
ddd	The abbreviated name of the day of the week.
dddd	The full name of the day of the week.
f	The tenths of a second.
ff	The hundredths of a second.
fff	The milliseconds.
ffff	The ten-thousandths of a second.
fffff	The hundred-thousandths of a second.
ffffff	The millionths of a second.
fffffff	The ten-millionths of a second.
g/gg	The period or era.
h	The hour, using a 12-hour clock from 1 to 12.
hh	The hour, using a 12-hour clock from 01 to 12.
H	The hour, using a 24-hour clock from 0 to 23.
HH	The hour, using a 24-hour clock from 00 to 23.
K	Time zone information.
m	The minute, from 0 through 59.
mm	The minute, from 00 through 59.
M	The month, from 1 through 12.
MM	The month, from 01 through 12.
MMM	The abbreviated name of the month.
MMMM	The full name of the month.
s	The second, from 0 through 59.
ss	The second, from 00 through 59.
t	The first character of the AM/PM designator.
tt	The AM/PM designator.
y	The year, from 0 to 99.
yy	The year, from 00 to 99.
yyy	The year, with a minimum of three digits.
yyyy	The year as a four-digit number.
yyyyy	The year as a five-digit number.
z	Hours offset from UTC, with no leading zero.
zz	Hours offset from UTC, with a leading zero for a single-digit value.
zzz	Hours and minutes offset from UTC.

The table shows custom date and time format specifiers in C#.

using System.Globalization;

var date = new DateTime(2022, 3, 26, 13, 44, 3, 672, DateTimeKind.Utc);

Console.WriteLine(date.ToString("M/d/yy", CultureInfo.GetCultureInfo("en-US")));
Console.WriteLine(date.ToString("MM/dd/yyyy", CultureInfo.GetCultureInfo("en-US")));
Console.WriteLine(date.ToString("yy-MM-dd", CultureInfo.GetCultureInfo("en-US")));
Console.WriteLine(date.ToString("yy-MMM-dd ddd", CultureInfo.GetCultureInfo("en-US")));
Console.WriteLine(date.ToString("yyyy-M-d dddd", CultureInfo.GetCultureInfo("en-US")));
Console.WriteLine(date.ToString("yyyy MMMM dd", CultureInfo.GetCultureInfo("en-US")));
Console.WriteLine(date.ToString("h:mm:ss tt zzz", CultureInfo.GetCultureInfo("en-US")));
Console.WriteLine(date.ToString("HH:m:s tt zzz", CultureInfo.GetCultureInfo("en-US")));
Console.WriteLine(date.ToString("hh:mm:ss t z", CultureInfo.GetCultureInfo("en-US")));
Console.WriteLine(date.ToString("HH:mm:ss tt zz", CultureInfo.GetCultureInfo("en-US")));

In the example, we build several custom date and time formats. The zzz and z results are based on the value's UTC kind.

$ dotnet run
3/26/22
03/26/2022
22-03-26
22-Mar-26 Sat
2022-3-26 Saturday
2022 March 26
1:44:03 PM +00:00
13:44:3 PM +00:00
01:44:03 P +0
13:44:03 PM +00

Parse datetime strings with format specifiers

Both standard and custom format specifiers can be used when parsing date and time strings into DateTime values. ParseExact requires the input to match the supplied format and culture exactly.

using System.Globalization;

var ds = "Thu Nov 11, 2021";
var dt = DateTime.ParseExact(ds, "ddd MMM dd, yyyy", CultureInfo.InvariantCulture);
Console.WriteLine(dt);

var ds2 = "10/22/2021";
var dt2 = DateTime.ParseExact(ds2, "d", CultureInfo.InvariantCulture);
Console.WriteLine(dt2);

In the example, we pass a custom format and a standard format to DateTime.ParseExact. The invariant culture makes the example independent of the machine's current culture.

$ dotnet run
11/11/2021 12:00:00 AM
10/22/2021 12:00:00 AM

Source

Custom date and time format strings

In this article we formatted DateTime values with standard and custom date and time format strings in C#.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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