How to convert timestamp to time ago in PHP?

A simple time_elapsed_string will do the job:

function time_elapsed_string($datetime, $full = false) {
  $now = new DateTime;
  $ago = new DateTime($datetime);
  $diff = $now->diff($ago);

  $diff->w = floor($diff->d / 7);
  $diff->d -= $diff->w * 7;

  $string = array(
    'y' => 'year',
    'm' => 'month',
    'w' => 'week',
    'd' => 'day',
    'h' => 'hour',
    'i' => 'minute',
    's' => 'second',
  );
  foreach ($string as $k => &$v) {
    if ($diff->$k) {
      $v = $diff->$k . ' ' . $v . ($diff->$k > 1 ? 's' : '');
    } else {
      unset($string[$k]);
    }
  }

  if (!$full) $string = array_slice($string, 0, 1);
    return $string ? implode(', ', $string) . ' ago' : 'just now';
  }

Usage example:

echo time_elapsed_string('2025-05-01 00:22:35');
echo time_elapsed_string('2025-05-01 00:22:35', true);

Output:

4 months ago
4 months, 2 weeks, 3 days, 1 hour, 49 minutes, 15 seconds ago