Scroll or zoom with the mouse wheel

You can use the mouse wheel to zoom in the Timeline, Composition, Layer, and Footage panels. You can use the mouse wheel to scroll in the Timeline, Project, Render Queue, Flowchart, Effect Controls, Metadata, and Effects & Presets panels.

To zoom into the center of the panel, or into the feature region when tracking, roll the mouse wheel forward.
To zoom out of the center of the panel, or out of the feature region when tracking, roll the mouse wheel backward.
To zoom into the area under the pointer, hold down Alt (Windows) or Option (Mac OS) as you roll the mouse wheel forward.
To zoom out of the area under the pointer, hold down Alt (Windows) or Option (Mac OS) as you roll the mouse wheel backward.
To scroll vertically, roll the mouse wheel forward or backward.
To scroll horizontally, hold down Shift as you roll the mouse wheel backward or forward. In the Timeline panel, Shift-rolling backward moves forward in time and vice versa.
You can scroll or zoom with the mouse wheel in a panel even if it is not currently active, as long as the pointer is over it. For example, you can zoom in the Composition panel even if the Effect Controls panel is currently active.