DateTimeZone::getOffset

timezone_offset_get

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

DateTimeZone::getOffset -- timezone_offset_get — Returns the timezone offset from GMT

Description

Object-oriented style

public DateTimeZone::getOffset(DateTimeInterface $datetime): int

Procedural style

timezone_offset_get (DateTimeZone $object, DateTimeInterface $datetime): int

This function returns the offset to GMT for the date/time specified in the datetime parameter. The GMT offset is calculated with the timezone information contained in the DateTimeZone object being used.

Parameters

object: Procedural style only: A DateTimeZone object returned by timezone_open()
datetime: DateTime that contains the date/time to compute the offset from.

Return Values

Returns time zone offset in seconds.

Examples

Example #1 DateTimeZone::getOffset() examples

<?php
// Create two timezone objects, one for Taipei (Taiwan) and one for
// Tokyo (Japan)
$dateTimeZoneTaipei = new DateTimeZone("Asia/Taipei");
$dateTimeZoneJapan = new DateTimeZone("Asia/Tokyo");

// Create two DateTime objects that will contain the same Unix timestamp, but
// have different timezones attached to them.
$dateTimeTaipei = new DateTime("now", $dateTimeZoneTaipei);
$dateTimeJapan = new DateTime("now", $dateTimeZoneJapan);

// Calculate the GMT offset for the date/time contained in the $dateTimeTaipei
// object, but using the timezone rules as defined for Tokyo
// ($dateTimeZoneJapan).
$timeOffset = $dateTimeZoneJapan->getOffset($dateTimeTaipei);

// Should show int(32400) (for dates after Sat Sep 8 01:00:00 1951 JST).
var_dump($timeOffset);

The above example will output:

int(32400)

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User Contributed Notes 1 note

down

Daniel Vidal ¶

3 years ago

Note that the DateTime parameter has no effect in the result returned by DateTimeZone::getOffset($DateTime), unless, it refers to a DateTime where there is daylight savings in the referenced DateTimeZone.
Ex.:
<?php
$timezone_brl = new DateTimeZone('America/Sao_Paulo');
$timezone_eng = new DateTimeZone('Europe/London');
$timezone_aus = new DateTimeZone('Australia/Brisbane');
$dateTimes = [
 new DateTime()
 , new DateTime('now', $timezone_eng)
 , new DateTime('now', $timezone_aus)
 , new DateTime('now', $timezone_brl)
 , new DateTime('2000-06-10', $timezone_brl)
 , new DateTime('2000-12-10', $timezone_brl)
 , new DateTime('2020-12-10', $timezone_brl)
];
foreach($dateTimes as $dateTime)
{
 echo "\n" . $timezone_brl->getOffset($dateTime);
}
/**
* -10800
* -10800
* -10800
* -10800
* -10800 // No daylight savings in June/2000
* - 7200 // Brazil had daylight savings until 2020
* -10800 // No more daylight savings, so it returns -10800
*/
?>

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