Calculate number of hours between 2 dates in PHP

Question

How do I calculate the difference between two dates in hours?

For example:

day1=2006-04-12 12:30:00
day2=2006-04-14 11:30:00

In thi

Answer 1

The easiest way to get the correct number of hours between two dates (datetimes), even across daylight saving time changes, is to use the difference in Unix timestamps. Unix timestamps are seconds elapsed since 1970-01-01T00:00:00 UTC, ignoring leap seconds (this is OK because you probably don't need this precision, and because it's quite difficult to take leap seconds into account).

The most flexible way to convert a datetime string with optional timezone information into a Unix timestamp is to construct a DateTime object (optionally with a DateTimeZone as a second argument in the constructor), and then call its getTimestamp method.

$str1 = '2006-04-12 12:30:00'; 
$str2 = '2006-04-14 11:30:00';
$tz1 = new DateTimeZone('Pacific/Apia');
$tz2 = $tz1;
$d1 = new DateTime($str1, $tz1); // tz is optional,
$d2 = new DateTime($str2, $tz2); // and ignored if str contains tz offset
$delta_h = ($d2->getTimestamp() - $d1->getTimestamp()) / 3600;
if ($rounded_result) {
   $delta_h = round ($delta_h);
} else if ($truncated_result) {
   $delta_h = intval($delta_h);
}
echo "Δh: $delta_h\n";