Change default event end time

Good day,

Is it possible to change the default event length? When I create a new event, the default length is 2 hours e.g. when I click on 07:00 am on the calendar, the ?New event? form displays the end time as 09:00 am.

I need to make the default length 30 mins.

Please advise.

//Schedule events in 30 minute increments
if ( {start_time} != ‘’) {
{end_time} = date(‘H:i’,strtotime(’+30 minutes’,strtotime({start_time})));
}