Follow the steps below to change Calendar Screen Size:
Login with Administrator privileges.
Click on System Preferences from Administration menu.
Under Calendar: Screen Size option, select the default time period calendars are displayed in. This setting acts in a similar fashion to a Zoom control with six levels. If you choose level 1, the calendars will show only one 'Block' of time, with each block defined by the Calendar: View By setting.
If you choose level 6, the calendar view will show six blocks of time. This control can be used to make sure you can display a time period that is compatible with your monitor resolution.