Office 365 (Outlook 2013 / 2016 / 2019 for Win) - How to Change the Calendar Time Scale
New appointments default to 30 minute increments. Here is how you to change the default duration time. Please note that the options may be grayed out in the month view but will be available to you in the day, week, and schedule views.
- Within Outlook, select Calendar from the navigation bar in the lower left.
- Select the View tab.
- The Time Scale selection is located in the Arrangement section of the ribbon.
- Click the drop down arrow and make your selection.
- This changes how your calendar is displayed and the default lengths for all appointments.