How to Change the Dock Size on a Macintosh Computer

Using System Preferences

1. 
   Log onto your computer. You'll need to be on the user you want to change the dock for.
2. 
   Open the System Preferences app. It looks like a grey icon with gears inside it. It should be present in the dock. If it is not there, check the Launchpad.

   1. You can also open it from the Apple menu. The Apple menu icon looks like the Apple logo. It is present in the extreme left of the menu bar. Click on it, and then click on the System Preferences option from the drop-down list that appears.
3. 
   Click on the dock option from the main System Preferences window. It is located in the topmost row of the window, and is depicted by a blue or black icon with white or blue icons inside it.
4. 
   Move the slider bar with the heading 'Size' to change the size of the dock. It is the first option in the menu. Move the slider left to make it smaller, and right to make it bigger. Note that the number of icons you have on the dock limits how much bigger you can make it.