(PHP 5 >= 5.3.0, PHP 7)
DateTime::getTimestamp -- DateTimeImmutable::getTimestamp -- DateTimeInterface::getTimestamp -- date_timestamp_get — Gets the Unix timestamp
Object oriented style
Procedural style
Gets the Unix timestamp.
This function has no parameters.
Returns the Unix timestamp representing the date.
Example #1 DateTime::getTimestamp() example
Object oriented style
<?php
$date = new DateTime();
echo $date->getTimestamp();
?>
Procedural style
<?php
$date = date_create();
echo date_timestamp_get($date);
?>
The above examples will output something similar to:
1272509157
Using U as the parameter to DateTime::format() is an alternative when using PHP 5.2.
Note that for dates before the unix epoch getTimestamp() will return false, whereas format("U") will return a negative number.
<?php
$date = new DateTime("1899-12-31");
// "-2209078800"
echo $date->format("U");
// false
echo $date->getTimestamp();
?>
In 32-bit system the unix timestamp will overflow if the date goes beyond year 2038 and this method will return false. In 64-bit systems this function will still work as intended. For more information please see http://en.wikipedia.org/wiki/Year_2038_problem.
Note that getTimestamp() does not return the UTC timestamp. It returns the timestamp relative to the set timezone, or the default server timezone. This also applies to dates in timezones with Daylight Savings.
<?php
// 11th March 2016 @ 11:00 UTC has timestamp: 1457694000
$d1 = new DateTime('2016-03-11 11:00:00', new DateTimeZone('Europe/Rome'));
$t1 = $d1->getTimestamp();
// 11th April 2016 @ 11:00 UTC has timestamp: 1460372400
$d2 = new DateTime('2016-04-11 11:00:00', new DateTimeZone('Europe/Rome'));
$t2 = $d2->getTimestamp();
printf("11 March: %d (diff = %d less)\n", $t1, 1457694000 - $t1);
printf("11 April: %d (diff = %d less)", $t2, 1460372400 - $t2);
// Prints:
// 1457690400 (diff = 3600)
// 1460365200 (diff = 7200)
