Zoom functionality is available by pressing Alt+P+Z or clicking on Project->Zoom. In the zoom menu there is the option (-) (Zoom in) or (+) (Zoom out) via buttons or via keyboard.
To focus on a specific time period or group of tasks, or to view the entire duration of your project, click Zoom on the Project menu, and then select a view option. To quickly magnify or shrink a view, click Zoom In  or Zoom Out 
The Zoom engine currently implements seven levels of details:
- One week level (the visible unit is one week).
- Two weeks level
- One month level (the visible unit is one month).
- Three months level
- Selected tasks
- Entire project
- Custom level: the user can select multiples of Days/Weeks/Months/Years to see in the chart panel or in the print preview format
Every time the view is selected it displays the chart information according to the zoom saved in MS Project for the respective view.
Note: The Zoom functionality is available in Gantt Chart, Tracking Gantt, Resource Graph, Network Diagram, Task Usage, Resource Usage and other related views.
In case the application is meant for mobile devices (phone, tablet), Zoom In and Zoom Out functionality will be available in all the supported views that will be triggered by touch gestures (the zoom will be made with two fingers) in the current view.
 This option is only available in Project Viewer for Win PC/Server, Project Viewer for MAC, Project Viewer for iPad, Project Viewer for Win Web/Server, Project Viewer Online Subscription, Project Viewer for SharePoint Server, Project Viewer for SharePoint Online, Project Plan 365 for Win PC/Server, Project Plan 365 for MAC, Project Plan 365 for iPad, Project Plan 365 for Win Web/Server, Project Plan 365 Online Subscription, Project Plan 365 for SharePoint Server and Project Plan 365 for SharePoint Online products