Apple Calendar 24 Hour Time. You can change the time format calendar uses to the 24 hour format by adjusting this setting in language & region preferences. Everyone is given the same 24 hours in a day, so we're here to try and use it as well as possible.
System clocks on both ipad and imac (mojave) are set to 12 hour am and pm clock but ical and calendar continue to display 24 hr time. To start the conversation again, simply ask a new question.