- floor: documentation ( source)
<?php
$minutes = 41;
$hours = 2;
$add = 30;
$new_minutes = ($minutes + $add) % 60;
$new_hours = floor(($minutes + $add) / 60);
echo "Previous: {$hours} hours, {$minutes} minutes.\n";
echo "Add {$add} minutes.\n";
echo "Current: {$new_hours} hours, {$new_minutes} minutes.";
?>