Convert day of the year to datetime in php

Question

I have value

$days = 166.0444; 

which is day of the year. How can I simply convert this value to its datetime, which should be

Answer 1

If its the current year, you can

$days = 166.0444;
$date = new DateTime();
$date->setDate($date->format('Y'), 1, 1);
$date->add(new DateInterval('P' . floor($days) . 'D'));