Date/Time
The PHP date() function is used to format a date and/or a time.
The function date() (and the DateTime object) can produce a variety of formatted time and date strings.
Date() Function
The PHP date() function formats a timestamp to a more readable date and time.
date(format,timestamp)
| Parameter | Description |
|---|---|
| format | Required. Specifies the format of the timestamp |
| timestamp | Optional. Specifies a timestamp. Default is the current date and time. A timestamp is a sequence of characters, denoting the date and/or time at which a certain event occurred. |
Get a Date
The required format parameter of the date() function specifies how to format the date (or time).
Here are some characters that are commonly used for dates:
- d - Represents the day of the month (01 to 31)
- m - Represents a month (01 to 12)
- Y - Represents a year (in four digits)
- l (lowercase 'L') - Represents the day of the week
Other characters, like"/", ".", or "-" can also be inserted between the characters to add additional formatting.
<?php
echo "Today is " . date("Y/m/d") . "<br>";
echo "Today is " . date("Y.m.d") . "<br>";
echo "Today is " . date("Y-m-d") . "<br>";
echo "Today is " . date("l");
© 2010-<?php echo date("Y");?> #Automatic Copyright Year
?>
Get a Time
Here are some characters that are commonly used for times:
- H - 24-hour format of an hour (00 to 23)
- h - 12-hour format of an hour with leading zeros (01 to 12)
- i - Minutes with leading zeros (00 to 59)
- s - Seconds with leading zeros (00 to 59)
- a - Lowercase Ante meridiem and Post meridiem (am or pm)
<?php
echo "The time is " . date("h:i:sa");
?>
PHP date() function will return the current date/time of the server.
Get Your Time Zone
If the time you got back from the code is not correct, it's probably because your server is in another country or set up for a different timezone.
So, if you need the time to be correct according to a specific location, you can set the timezone you want to use.
<?php
date_default_timezone_set('America/New_York');
echo "The time is " . date("h:i:sa");
?>
DateTime Object
The DateTime object can be used to format a date and/or a time.
<?php
$d = new DateTime();
echo $d->format('Y-m-d H:i:s');
?>
Use getdate() or localtime() if you want time parts.
<?php
$now_1 = getdate();
$now_2 = localtime();
print "{$now_1['hours']}:{$now_1['minutes']}:{$now_1['seconds']}\n";
print "$now_2[2]:$now_2[1]:$now_2[0]";
?>
18:23:45
18:23:45
Use DateTime::createFromFormat() if you want date parts.
<?php
// 7:45:03 PM on March 10, 1975, in a particular timezone
$then = DateTime::createFromFormat(DateTime::ATOM, "1975-03-10T19:45:03-04:00");
?>
The createFromFormat() method of the DateTime class behaves more flexibly. Instead of accepting already-chopped-up time parts, you give it a formatted time or date string and tell it the structure of that string. It then decomposes the parts properly and calculates the correct timestamp. In addition to the format strings listed in Recipe 3.4 that the date() function understands, createFromFormat() also uses the characters listed below.
| Character | Meaning |
|---|---|
| space or tab | |
| # | Any one of the separation bytes ;, :, /, ., ,, -, (, ) |
| ;, :, /, ., ,, -, (, ) | Literal character |
| ? | Any byte (not a character, just one byte) |
| * | Any number of bytes until the next digit or separation character |
| ! | Resetall fieldsto“startof Unixepoch”values(without this,anyunspecifiedfieldswillbeset tothecurrent |
| date/time) | |
| | | Reset any unparsed fields to “start of Unix epoch” values |
| + | Treat unparsed trailing data as a warning rather than an error |
<?php
$text = "Birthday: May 11, 1918.";
$when = DateTime::createFromFormat("*: F j, Y.|", $text);
// $formatted is "Saturday, 11-May-18 00:00:00 UTC"
$formatted = $when->format(DateTime::RFC850);
?>
<?php
$when = new DateTime("@163727100");
$when->setTimezone(new DateTimeZone('America/Los_Angeles'));
$parts = explode('/', $when->format('Y/m/d/H/i/s'));
// Year, month, day, hour, minute, second
// $parts is array('1975', '03','10', '16','45', '00'))
?>
getdate()
Both localtime() and getdate() return arrays whose elements are the different pieces of the specified date and time. The associative array getdate() returns the key/value pairs listed below.
| Key | Value |
|---|---|
| seconds | Seconds |
| minutes | Minutes |
| hours | Hours |
| mday | Day of the month |
| wday | Day of the week, numeric (Sunday is 0, Saturday is 6) |
| mon | Month, numeric |
| year | Year, numeric (4 digits) |
| yday | Day of the year, numeric (e.g., 299) |
| weekday | Day of the week, textual, full (e.g., “Friday”) |
| month | Month, textual, full (e.g., “January”) |
| 0 | Seconds since epoch (what time() returns) |
<?php
//Finding the month, day, and year
$a = getdate();
printf('%s %d, %d',$a['month'],$a['mday'],$a['year']);
?>
January 10, 2023
localtime()
The function localtime() also returns an array of time and date parts. It also takes an epoch timestamp as an optional first argument, as well as a boolean as an optional second argument. If that second argument is true, localtime() returns an associative array instead of a numerically indexed array. The keys of that array are the same as the members of the tm_struct structure that the C function localtime() returns, as shown below.
| Numeric position | Key Value |
|---|---|
| 0 | tm_sec Second |
| 1 | tm_min Minutes |
| 2 | tm_hour Hour |
| 3 | tm_mday Day of the month |
| 4 | tm_mon Month of the year (January is 0) |
| 5 | tm_year Years since 1900 |
| 6 | tm_wday Day of the week (Sunday is 0) |
| 7 | tm_yday Day of the year |
| 8 | tm_isdst Is daylight saving time in effect? |
<?php
$a = localtime();
$a[4] += 1;
$a[5] += 1900;
print "$a[4]/$a[3]/$a[5]";
?>
1/10/2023
The month is incremented by 1 before printing because localtime() starts counting months with 0 for January, but we want to display 1 if the current month is January. Similarly, the year is incremented by 1900 because localtime() starts counting years with 0 for 1900.
The functions getdate() and localtime() both use the same internal implementation to generate the returned date and time parts. They differ only in the format of the returned arrays and in some of the information they return. (For example, local time() includes whether DST is in effect at the specified time.)
mktime()
The optional timestamp parameter in the date() function specifies a timestamp. If omitted, the current date and time will be used (as in the examples above).
The PHP mktime() function returns the Unix timestamp for a date. The Unix timestamp contains the number of seconds between the Unix Epoch (January 1 1970 00:00:00 GMT) and the time specified.
Use mktime() if your time and date parts are in the local time zone.
Syntax
mktime(hour, minute, second, month, day, year)
<?php
$d=mktime(11, 14, 54, 8, 12, 2014);
echo "Created date is " . date("Y-m-d h:i:sa", $d);
?>
The functions mktime() and gmmktime() each take a date and time’s parts (hour, minute, second, month, day, year) and return the appropriate Unix epoch timestamp. The components are treated as local time by mktime(), while gmmktime() treats them as a date and time in UTC.
gmktime()
Use gmmktime() if your time and date parts are in the GMT time zone.
<?php
// 7:45:03 PM on March 10, 1975, in GMT
$then = gmmktime(19,45,3,3,10,1975);
?>
Create a Date From a String With strtotime()
The PHP strtotime() function is used to convert a human readable date string into a Unix timestamp (the number of seconds since January 1 1970 00:00:00 GMT).
Syntax
strtotime(time, now)
<?php
$d=strtotime("10:30pm April 15 2014");
echo "Created date is " . date("Y-m-d h:i:sa", $d);
?>
<?php
$d=strtotime("tomorrow");
echo date("Y-m-d h:i:sa", $d) . "<br>";
$d=strtotime("next Saturday");
echo date("Y-m-d h:i:sa", $d) . "<br>";
$d=strtotime("+3 Months");
echo date("Y-m-d h:i:sa", $d) . "<br>";
?>
<?php
$d=strtotime("last Sunday");
echo date("Y-m-d h:i:sa", $d) . "<br>";
$startdate = strtotime("Saturday");
$enddate = strtotime("+6 weeks", $startdate);
while ($startdate < $enddate) {
echo date("M d", $startdate) . "<br>";
$startdate = strtotime("+1 week", $startdate);
}
?>
<?php
$d1=strtotime("July 04");
$d2=ceil(($d1-time())/60/60/24);
echo "There are " . $d2 ." days until 4th of July.";
?>
If you find yourself with a date or time string with a known format, but that is not parseable by strtotime(), you can still create DateTime objects based on the string by using DateTime::createFromFormat().
<?php
$dates = array('01/02/2015', '03/06/2015', '09/08/2015');
foreach ($dates as $date) {
$default = new DateTime($date);
$day_first = DateTime::createFromFormat('d/m/Y|', $date);
printf("The default interpretation is %s\n but day-first is %s.\n",
$default->format(DateTime::RFC850),
$day_first->format(DateTime::RFC850));
}
?>
The default interpretation is Friday, 02-Jan-15 00:00:00 UTC
but day-first is Sunday, 01-Feb-15 00:00:00 UTC.
The default interpretation is Friday, 06-Mar-15 00:00:00 UTC
but day-first is Wednesday, 03-Jun-15 00:00:00 UTC.
The default interpretation is Tuesday, 08-Sep-15 00:00:00 UTC
but day-first is Sunday, 09-Aug-15 00:00:00 UTC.
Printing a Date or Time in a Specified Format
Both date() and DateTime::format() use the same code internally for generating formatted time and date strings. They are flexible functions that can produce a formatted time string with a variety of components. The format characters for these functions are listed below.
| Type | Character | Description | Range or examples |
|---|---|---|---|
| Hour | H | Hour, numeric, 24-hour clock, leading zero | 00–23 |
| Hour | h | Hour, numeric, 12-hour clock, leading zero | 01–12 |
| Hour | G | Hour, numeric, 24-hour clock | 0–23 |
| Hour | g | Hour, numeric, 12-hour clock | 1–12 |
| Hour | A | Ante/Post Meridiem designation | AM, PM |
| Hour | a | Ante/Post Meridiem designation | am, pm |
| Minute | i | Minute, numeric | 00–59 |
| Second | s | Second, numeric | 00–59 |
| Second | u | Microseconds, string | 000000–999999 |
| Day | d | Day of the month, numeric, leading zero | 01–31 |
| Day | j | Day of the month, numeric | 1–31 |
| Day | z | Day of the year, numeric | 0–365 |
| Day | N | Day of the week, numeric (Monday is 1) | 1–7 |
| Day | w | Day of the week, numeric (Sunday is 0) | 0–6 |
| Day | S | Englishordinalsuffixfordayofthemonth,textual | “st,” “th,” “nd,” “rd” |
| Week | D | Abbreviated weekday name | Mon, Tue, Wed, Thu, Fri, Sat, Sun |
| Week | l | Full weekday name | Monday, Tuesday, Wednesday Thursday, Friday, Saturday, Sunday |
| Week | W | ISO8601:1988 week number in the year,numeric, week 1 is the first week that has at least 4 days in the current year, Monday is the first day of the week | 1–53 |
| Month | F | Full month name | January–December |
| Month | M | Abbreviated month name | Jan–Dec |
| Month | m | Month, numeric, leading zero | 01–12 |
| Month | n | Month, numeric | 1–12 |
| Month | t | Month length in days, numeric | 28, 29, 30, 31 |
| Year | Y | Year, numeric, including century | e.g., 2016 |
| Year | y | Year without century, numeric | e.g., 16 |
| Year | o | ISO 8601 year with century; numeric; the fourdigityearcorrespondingtotheISOweek number; sameas Y exceptiftheISOweek number belongs to the previous or next year, that year is used instead | e.g. 2016 |
| Year | L | Leap year flag (yes is 1) | 0, 1 |
| Time zone | O | Hour offset from GMT, ±HHMM (e.g., −0400, +0230) | −1200–+1200 |
| Time zone | P | Like O, but with a colon −12:00 | –+12:00 |
| Time zone | Z | Seconds offset from GMT; west of GMT is negative, east of GMT is positive | -43200–50400 |
| Time zone | e | Time zone identifier | e.g., America/New_York |
| Time zone | T | Time zone abbreviation | e.g., EDT |
| Time zone | I | Daylight saving time flag (yes is 1) | 0, 1 |
| Compound | c | ISO 8601–formatted date and time | e.g., 2012-09-06T15:29:34+0000 |
| Compound | r | RFC 2822–formatted date | e.g., Thu, 22 Aug 2002 16:01:07 +0200 |
| Other | U | Seconds since the Unix epoch | 0−2147483647 |
| Other | B | Swatch Internet time | 000–999 |
Format characters such as F, M, or D, which generate words, not numbers, produce output in English.
There are also some handy constants for common date formats that represent the format string to be passed to date() or DateTime::format(). These constants are listed below.
| Constant | Class constant | Value | Example | Usage |
|---|---|---|---|---|
| DATE_ATOM | DateTime::ATOM | Y-m-d TH:i:sP |
2013-02-22 T20:25:31+00:00 |
Atom Syndication format |
| DATE_ISO8601 | DateTime::ISO8601 | Y-m-d TH:i:sO |
2013-02-22 T20:25:31+0000 |
ISO 8601 |
| DATE_RFC822 | DateTime::RFC822 | D, d M y H:i:s O |
Fri, 22 Feb 13 20:25:31 +0000 |
Email messages |
| DATE_RFC850 | DateTime::RFC850 | l, d-M-y H:i:s T |
Friday, 22-Feb-13 20:25:31 UTC |
Usenet messages |
| DATE_RFC1036 | DateTime::RFC1036 | D, d M y H:i:s O |
Fri, 22 Feb 13 20:25:31 +0000 |
Usenet messages |
| DATE_RFC1123 | DateTime::RFC1123 | D, d M Y H:i:s O |
Fri, 22 Feb 2013 20:25:31 +0000 |
|
| DATE_RFC2822 | DateTime::RFC2822 | D, d M Y H:i:s O |
Fri, 22 Feb 2013 20:25:31 +0000 |
E-mail messages |
| DATE_RFC3339 | DateTime::RFC3339 | Y-m-d TH:i:sP |
2013-02-22 T20:25:31+00:00 |
|
| DATE_RSS | DateTime::RSS | D, d M Y H:i:s O |
Fri, 22 Feb 2013 20:25:31 +0000 |
RSS feeds |
| DATE_W3C | DateTime::W3C | Y-m-d TH:i:sP |
2013-02-22 T20:25:31+00:00 |
Calculating the difference between two dates
<?php
// 7:32:56 pm on May 10, 1965
$first = new DateTime("1965-05-10 7:32:56pm",
new DateTimeZone('America/New_York'));
// 4:29:11 am on November 20, 1962
$second = new DateTime("1962-11-20 4:29:11am",
new DateTimeZone('America/New_York'));
$diff = $second->diff($first);
printf("The two dates have %d weeks, %s days, " .
"%d hours, %d minutes, and %d seconds " .
"elapsed between them.",
floor($diff->format('%a') / 7),
$diff->format('%a') % 7,
$diff->format('%h'),
$diff->format('%i'),
$diff->format('%s'));
?>
The two dates have 128 weeks, 6 days, 15 hours, 3 minutes, and 45 seconds elapsed between them.
<?php
//Calculating the elapsed-time difference between two dates
// 7:32:56 pm on May 10, 1965
$first_local = new DateTime("1965-05-10 7:32:56pm",
new DateTimeZone('America/New_York'));
// 4:29:11 am on November 20, 1962
$second_local = new DateTime("1962-11-20 4:29:11am",
new DateTimeZone('America/New_York'));
$first = new DateTime('@' . $first_local->getTimestamp());
$second = new DateTime('@' . $second_local->getTimestamp());
$diff = $second->diff($first);
printf("The two dates have %d weeks, %s days, " .
"%d hours, %d minutes, and %d seconds " .
"elapsed between them.",
floor($diff->format('%a') / 7),
$diff->format('%a') % 7,
$diff->format('%h'),
$diff->format('%i'),
$diff->format('%s'));
?>
The two dates have 128 weeks, 6 days, 14 hours, 3 minutes, and 45 seconds elapsed between them.
The DateTime objects created with a format string of @ plus an epoch timestamp always have a time zone of UTC, so their difference is not affected by any daylight saving time or other local time adjustments.
Adding and subtracting a date interval
The add() and sub() methods of DateTime modify the DateTime method they are called on by whatever amount is specified in the interval. The average human gestation time is 40 weeks, so an interval of P40W walks back the birthday to 40 weeks earlier, approximating conception time.
<?php
$birthday = new DateTime('March 10, 1975');
// When is 40 weeks before $birthday?
$human_gestation = new DateInterval('P40W');
$birthday->sub($human_gestation);
print $birthday->format(DateTime::RFC850);
print "\n";
// What if it was an elephant, not a human?
$elephant_gestation = new DateInterval('P616D');
$birthday->add($elephant_gestation);
print $birthday->format(DateTime::RFC850);
?>
A DateTime object’s modify() method accepts, instead of a DateInterval object, a string that strtotime() understands. This provides an easy way to find relative dates like “next Tuesday” from a given object.
<?php
$year = 2016;
$when = new DateTime("November 1, $year");
if ($when->format('D') != 'Mon') {
$when->modify("next Monday");
}
$when->modify("next Tuesday");
print "In $year, US election day is on the " .
$when->format('jS') . ' day of November.';
?>
Finding the Day in a Week, Month, or Year
When you want to know the day or week of the year, the day of the week, or the day of the month. For example, you want to print a special message every Monday, or on the first of every month.
<?php
print "Today is day " . date('d') . ' of the month and ' . date('z') .
' of the year.';
print "\n";
$birthday = new DateTime('January 17, 1706', new DateTimeZone('America/New_York'));
print "Benjamin Franklin was born on a " . $birthday->format('l') . ", " .
"day " . $birthday->format('N') . " of the week.";
?>
The functions date() and DateTime::format() use the same format characters.
| Type | Character | Description | Range |
|---|---|---|---|
| Day | d | Day of the month, numeric, leading zero | 01–31 |
| Day | j | Day of the month, numeric | 1–31 |
| Day | z | Day of the year, numeric | 0–365 |
| Day | N | Day of the week, numeric (Monday is 1) | 1–7 |
| Day | w | Day of the week, numeric (Sunday is 0) | 0–6 |
| Day | S | English ordinal suffix for day of the month, textual | st, th,nd, rd |
| Week | D | Abbreviated weekday name | Mon, Tue, Wed, Thu, Fri, Sat, Sun |
| Week | l | Full weekday name | Monday, Tuesday, Wednesday, Thursday, Friday, Saturday,Sunday |
| Week | W | ISO 8601:1988 week number in the year, numeric, week 1 is the first week that has at least 4 days in the current year, Monday is the first day of the week | 1–53 |
Validating Dates
The function checkdate() returns true if $month is between 1 and 12, $year is between 1 and 32767, and $day is between 1 and the correct maximum number of days for $month and $year. Leap years are correctly handled by checkdate(), and dates are rendered using the Gregorian calendar.
<?php
// $ok is true - March 10, 1993 is a valid date
$ok = checkdate(3, 10, 1993);
// $not_ok is false - February 30, 1962 is not a valid date
$not_ok = checkdate(2, 30, 1962);
?>
<?php
checkbirthdate()
function checkbirthdate($month,$day,$year) {
$min_age = 18;
$max_age = 122;
if (! checkdate($month,$day,$year)) {
return false;
}
$now = new DateTime();
$then_formatted = sprintf("%d-%d-%d", $year, $month, $day);
$then = DateTime::createFromFormat("Y-n-j|",$then_formatted);
$age = $now->diff($then);
if (($age->y < $min_age)|| ($age->y > $max_age)) {
return FALSE;
}
else {
return TRUE;
}
}
// check December 3, 1974
if (checkbirthdate(12,3,1974)) {
print "You may use this web site.";
} else {
print "You are too young (or too old!!) to proceed.";
}
?>
Generating a High-Precision Time
When you need to measure time with finer than one-second resolution—for example, to gen‐ erate a unique ID or benchmark a function call.
<?php
$start = microtime(true);
for ($i = 0; $i < 1000; $i++) {
preg_match('/age=\d{1,5}/',$_SERVER['QUERY_STRING']);
}
$end = microtime(true);
$elapsed = $end - $start;
?>
Generating Time Ranges
When you need to generate a range of dates or times. Use the DatePeriod class, available starting with PHP 5.3.0. Its constructor accepts a flexible combination of options that lets you control the range length, time between items in the range, and how many items there are in the range.
<?php
// Start on August 1
$start = new DateTime('August 1, 2014');
// End date is exclusive, so this will stop on August 31
$end = new DateTime('September 1, 2014');
// Go 1 day at a time
$interval = new DateInterval('P1D');
$range1 = new DatePeriod($start, $interval, $end);
?>
Here’s another way to do the same thing:
<?php
// Start on August 1
$start = new DateTime('August 1, 2014');
// Go 1 day at a time
$interval= new DateInterval('P1D');
// Recur 30 times more after the first occurrence.
$recurrences = 30;
$range2 = new DatePeriod($start, $interval, $recurrences);
?>
and a third way:
<?php
// using the ISO 8601 specified format for describing date ranges
$range3 = new DatePeriod('R30/2014-08-01T00:00:00Z/P1D');
foreach ($range1 as $d) {
print "A day in August is " . $d->format('d') . "\n";
}
?>