Format the time and/or date according to locale settings. Month and weekday names and other language-dependent strings respect the current locale set with setlocale.
Not all conversion specifiers may be supported by your C library, in which case they will not be supported by PHP's strftime. Additionally, not all platforms support negative timestamps, so your date range may be limited to no earlier than the Unix epoch. This means that %e, %T, %R and, %D (and possibly others) - as well as dates prior to Jan 1, 1970 - will not work on Windows, some Linux distributions, and a few other operating systems. For Windows systems, a complete overview of supported conversion specifiers can be found at MSDN.
The following characters are recognized in the format parameter string
format Description Example returned values Day --- --- %a An abbreviated textual representation of the day Sun through Sat %A A full textual representation of the day Sunday through Saturday %d Two-digit day of the month (with leading zeros) 01 to 31 %e Day of the month, with a space preceding single digits. Not implemented as described on Windows. See below for more information. 1 to 31 %j Day of the year, 3 digits with leading zeros 001 to 366 %u ISO-8601 numeric representation of the day of the week 1 (for Monday) through 7 (for Sunday) %w Numeric representation of the day of the week 0 (for Sunday) through 6 (for Saturday) Week --- --- %U Week number of the given year, starting with the first Sunday as the first week 13 (for the 13th full week of the year) %V ISO-8601:1988 week number of the given year, starting with the first week of the year with at least 4 weekdays, with Monday being the start of the week 01 through 53 (where 53 accounts for an overlapping week) %W A numeric representation of the week of the year, starting with the first Monday as the first week 46 (for the 46th week of the year beginning with a Monday) Month --- --- %b Abbreviated month name, based on the locale Jan through Dec %B Full month name, based on the locale January through December %h Abbreviated month name, based on the locale (an alias of %b) Jan through Dec %m Two digit representation of the month 01 (for January) through 12 (for December) Year --- --- %C Two digit representation of the century (year divided by 100, truncated to an integer) 19 for the 20th Century %g Two digit representation of the year going by ISO-8601:1988 standards (see %V) Example: 09 for the week of January 6, 2009 %G The full four-digit version of %g Example: 2008 for the week of January 3, 2009 %y Two digit representation of the year Example: 09 for 2009, 79 for 1979 %Y Four digit representation for the year Example: 2038 Time --- --- %H Two digit representation of the hour in 24-hour format 00 through 23 %k Hour in 24-hour format, with a space preceding single digits 0 through 23 %I Two digit representation of the hour in 12-hour format 01 through 12 %l (lower-case 'L') Hour in 12-hour format, with a space preceding single digits 1 through 12 %M Two digit representation of the minute 00 through 59 %p UPPER-CASE 'AM' or 'PM' based on the given time Example: AM for 00:31, PM for 22:23 %P lower-case 'am' or 'pm' based on the given time Example: am for 00:31, pm for 22:23 %r Same as "%I:%M:%S %p" Example: 09:34:17 PM for 21:34:17 %R Same as "%H:%M" Example: 00:35 for 12:35 AM, 16:44 for 4:44 PM %S Two digit representation of the second 00 through 59 %T Same as "%H:%M:%S" Example: 21:34:17 for 09:34:17 PM %X Preferred time representation based on locale, without the date Example: 03:59:16 or 15:59:16 %z The time zone offset. Not implemented as described on Windows. See below for more information. Example: -0500 for US Eastern Time %Z The time zone abbreviation. Not implemented as described on Windows. See below for more information. Example: EST for Eastern Time Time and Date Stamps --- --- %c Preferred date and time stamp based on locale Example: Tue Feb 5 00:45:10 2009 for February 5, 2009 at 12:45:10 AM %D Same as "%m/%d/%y" Example: 02/05/09 for February 5, 2009 %F Same as "%Y-%m-%d" (commonly used in database datestamps) Example: 2009-02-05 for February 5, 2009 %s Unix Epoch Time timestamp (same as the time function) Example: 305815200 for September 10, 1979 08:40:00 AM %x Preferred date representation based on locale, without the time Example: 02/05/09 for February 5, 2009 Miscellaneous --- --- %n A newline character ("\n") --- %t A Tab character ("\t") --- %% A literal percentage character ("%") ---
Contrary to ISO-9899:1999, Sun Solaris starts with Sunday as 1. As a result, %u may not function as described in this manual.
The %e modifier is not supported in the Windows implementation of this function. To achieve this value, the %#d modifier can be used instead. The example below illustrates how to write a cross platform compatible function.
The %z and %Z modifiers both return the time zone name instead of the offset or abbreviation.
macOS and musl only: The %P modifier is not supported in the macOS implementation of this function.
The optional timestamp parameter is an int Unix timestamp that defaults to the current local time if timestamp is omitted or null. In other words, it defaults to the value of time.
Returns a string formatted according format using the given timestamp or the current local time if no timestamp is given. Month and weekday names and other language-dependent strings respect the current locale set with setlocale. The function returns false if format is empty, contains unsupported conversion specifiers, or if the length of the returned string would be greater than 4095.
Exceptions and Errors
Every call to a date/time function will generate a E_WARNING if the time zone is not valid. See also date_default_timezone_set
As the output is dependent upon the underlying C library, some conversion specifiers are not supported. On Windows, supplying unknown conversion specifiers will result in 5 E_WARNING messages and return false. On other operating systems you may not get any E_WARNING messages and the output may contain the conversion specifiers unconverted.
%G and %V, which are based on ISO 8601:1988 week numbers can give unexpected (albeit correct) results if the numbering system is not thoroughly understood. See %V examples in this manual page.
|8.0.0||timestamp is nullable now.|