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Get to Know Functions and Constants Used for PHP DateTime Format

Reading time 5 min
Published Aug 8, 2017
Updated Oct 15, 2019

PHP date and time can be formatted in multiple different ways in your PHP code. You might need a Unix timestamp or GMT date, a DateTime object or an ISO date. Therefore, it is important to learn functions that are applied to manipulate PHP DateTime format.

PHP date formatting is not that hard, but you still have to have specific knowledge and expertise. Fetching the date and time from the server you are using is only the first step. Don't let a wrong time zone or PHP date format throw you off your feet!

PHP DateTime Format: Main Tips

  • Time and date PHP functions allow you to get date and time from the server you're using.
  • These functions are inbuilt into the PHP core.
  • Keep in mind that these functions are dependant on your server's locale setting.

Runtime Configuration

When using these functions to set PHP DateTime format, remember that how they behave will be affected by the settings located in php.ini:

Name Description Default PHP Version
date.timezone Default timezone (is used by all PHP date/time functions) "" PHP 5.1 and newer
date.default_latitude Default latitude (is used by date_sunrise() and date_sunset()) "31.7667" PHP 5.0 and newer
date.default_longitude Default longitude (is used by date_sunrise() and date_sunset()) "35.2333" PHP 5.0 and newer
date.sunrise_zenith Default sunrise zenith (is used by date_sunrise() and date_sunset()) "90.83" PHP 5.0 and newer
date.sunset_zenith Default sunset zenith (is used by date_sunrise() and date_sunset()) "90.83" PHP 5.0 and up

Time And Date Functions

Analyze the table below. It is a handy guide for the inbuilt functions that can be used for all your needs when it comes to setting the PHP DateTime format. Feel free to return to it whenever you need a reminder.

Function Description
checkdate() Validate Gregorian date
date_add() Add days, months, years, hours, minutes, and seconds to date
date_create_from_format() Return new DateTime object formatted according to specified format
date_create() Return new DateTime object
date_date_set() Set new date
date_default_timezone_get() Return default timezone used by all PHP date/time functions
date_default_timezone_set() Set default timezone used by all PHP date/time functions
date_diff() Return difference between two PHP dates
date_format() Return PHP date formatted according to specified format
date_get_last_errors() Return warnings/errors found in PHP date string
date_interval_create_from_date_string() Set up PHP DateInterval from relative parts of string
date_interval_format() Format interval
date_isodate_set() Set ISO date
date_modify() Modify PHP timestamp
date_offset_get() Return timezone offset
date_parse_from_format() Return associative array with detailed info about specified date, according to specified format
date_parse() Return associative array with detailed info about specified date
date_sub() Subtract days, months, years, hours, minutes, and seconds from date
date_sun_info() Return array containing info about sunset/sunrise and twilight begin/end, for specified day and location
date_sunrise() Return sunrise time for specified day and location
date_sunset() Return sunset time for specified day and location
date_time_set() Set PHP time
date_timestamp_get() Return Unix PHP timestamp
date_timestamp_set() Set date and time based on Unix PHP timestamp
date_timezone_get() Return time zone of given DateTime object
date_timezone_set() Set time zone for DateTime object
date() Format local date and time
getdate() Return date/time information of PHP timestamp or current local date/time
gettimeofday() Return current time
gmdate() Format GMT/UTC date and time
gmmktime() Return Unix PHP timestamp for GMT date
gmstrftime() Format GMT/UTC date and time according to locale settings
idate() Format local time/date as int
localtime() Return local time
microtime() Return currently available Unix PHP timestamp in microseconds
mktime() Return Unix PHP timestamp for date
strftime() Format local time and/or date according to locale settings
strptime() Parse time/date generated with strftime()
strtotime() Parse English textual datetime into Unix PHP timestamp
time() Return current time as Unix PHP timestamp
timezone_abbreviations_list() Return associative array containing dst, offset, and timezone name
timezone_identifiers_list() Return indexed array with all timezone identifiers
timezone_location_get() Return location information for a specified timezone
timezone_name_from_ abbr() Returns the timezone name from abbreviation
timezone_name_get() Return name of timezone
timezone_offset_get() Return timezone offset from GMT
timezone_open() Create new DateTimeZone object
timezone_transitions_get() Return all transitions for timezone
timezone_version_get() Return version of timezone db

List of Predefined Constants

There are also a few predefined constants that can be used in PHP date formatting. Take a look at their names and descriptions:

Constant Description
DATE_ATOM Atom (i.e.: 2005-08-17T16:15:03+0000)
DATE_COOKIE HTTP Cookies (i.e.: Sun, 18 Aug 2005 14:13:03 UTC)
DATE_ISO8601 ISO-8601 (i.e.: 2005-08-14T17:13:03+0000)
DATE_RFC822 RFC 822 (i.e.: Sun, 14 Aug 2006 16:12:03 UTC)
DATE_RFC850 RFC 850 (i.e.: Sunday, 14-Aug-06 16:13:03 UTC)
DATE_RFC1036 RFC 1036 (i.e.: Sunday, 14-Aug-04 16:13:03 UTC)
DATE_RFC1123 RFC 1123 (i.e.: Sun, 14 Aug 2006 16:13:03 UTC)
DATE_RFC2822 RFC 2822 (i.e.:Sun, 14 Aug 2006 16:13:03 +0000)
DATE_RSS RSS (i.e.:Sun, 14 Aug 2006 17:15:04 UTC)
DATE_W3C World Wide Web Consortium (i.e.: 2007-09-14T16:11:05+0000)

PHP DateTime Format: Summary

  • To get dates and time, inbuilt PHP time and date functions and constants are used.
  • These functions are related to the locale settings of the server you're using.
  • Always keep time inconsistencies (such as daylight savings, time zones and leap years) in mind when working with PHP date functions.