Calendar has several options for customizing how many days and hours are shown. You can customize the Week view to show all seven days of the week or just Monday through Friday. You can customize the Day and Week views so that the Calendar window shows from 6 to 24 hours of events per day, and you can mark when your day starts and ends.
Choose Calendar > Preferences, then click General.
Click the “Days per week” pop-up menu, then choose whether to show 5 or 7 days.
Click the “Day starts at” and “Day ends at” pop-up menus, then choose when your days start and end.