How to convert date timezone in PHP?

You can use the DateTime object or their function aliases for this:

date_default_timezone_set('Europe/London');

$datetime = new DateTime('2025-07-03 10:00:00');
echo $datetime->format('Y-m-d H:i:s') . "\n";
$la_time = new DateTimeZone('America/Los_Angeles');
$datetime->setTimezone($la_time);
echo $datetime->format('Y-m-d H:i:s');