datetime diff php in hours code example

Example 1: date diff php

$datetime1 	= new DateTime('2020-10-11 16:52:52');
$datetime2 	= new DateTime('2020-10-13 16:52:52');
$interval 	= $datetime1->diff($datetime2);

echo $interval->format('%a days');

Example 2: php time difference in hours

date_default_timezone_set("Africa/Johannesburg");
    $now = new DateTime();
    $future_date = new DateTime('2020-10-21 00:00:00');
    
    $interval = $future_date->diff($now);
    
    echo ($interval->format("%a") * 24) + $interval->format("%h"). " hours". $interval->format(" %i minutes ");
    print_r($now->format('Y-m-d H:i:s'));