Change Presentation Aspect Ratio from Widescreen to Standard (and Vice Versa) in PowerPoint Online

PowerPoint Online defaults to widescreen slides in all new presentations. However, you can change your presentation's aspect ratio from Widescreen (16:9) to Standard (4:3), and also do the reverse. PowerPoint Online has some features up its sleeve that make these changes of aspect ratios easier to understand, and some quirks too! This tutorial will help you understand both scenarios better.

Change from Widescreen to Standard Aspect Ratio

Follow these steps to learn how you can easily change the aspect ratio of your slides from Widescreen to Standard:

1. Launch PowerPoint Online. This opens the Presentation Gallery. Within the Presentation Gallery, chose any Theme. For this tutorial we choose the Ion Boardroom theme, as shown highlighted in red within Figure 1.
2. 
   Figure 1: Ion Boardroom Theme selected within the Presentation gallery
2. This creates a new presentation within PowerPoint Online using the Ion Boardroom theme (see Figure 2). We added some content to this slide. Notice that the Slide Area now displays a Widescreen (16:9) slide, highlighted in blue within Figure 2.
3. 
   Figure 2: Widescreen slide
3. Now, access the Design tab of the Ribbon, and locate the Slide Size button, as shown highlighted in blue within Figure 3.
4. 
   Figure 3: Slide Size button within the Design tab of the Ribbon
4. Click the Slide Size button to bring up a drop-down gallery, as shown in Figure 4. Within this gallery, choose the Standard (4:3) slide size for your presentation.
5. 
   Figure 4: Slide Size drop-down gallery
5. This brings up the Slide Scale window, as shown in Figure 5. Note that you may not see this dialog box on changing the aspect ratio of your slides if you are using a proprietary on an older Theme.
6. 
   Figure 5: Slide Scale
7. The above window (see Figure 5) provides two options, explained below:
8. Maximize: Select this option to discard content on the sides of your slide. This could make your content appear larger, but you’ll lose some content on your slide.
9. Ensure Fit: Select this option to retain all slide content, and add more slide real estate on the top and bottom areas of your slide. This could make your content appear smaller, but you’ll be able to see all content on your slide.
10. Make your choice based on what works for you. Remember that you can quickly press Ctrl+Z to undo any changes if you are not happy with the results. You can also click the Cancel button to not change the aspect ratio at this time.
6. If you choose either of the Maximize or Ensure Fit options in the preceding step, you'll successfully change your presentation's slide aspect ratio (highlighted in blue within Figure 6). Figures 6 and 7 show the presentation's aspect ratio changed to 4:3 using both the Maximize and Ensure Fit options. Compare both these slides with the slide you viewed previously in Figure 2.
7. 
   Figure 6: Widescreen slide changed to Standard size with Maximize option selected
8. 
   Figure 7: Widescreen slide changed to Standard size with Ensure Fit option selected
7. Make sure you save your presentation.

Change from Standard to Widescreen Aspect Ratio

Follow these steps to learn how you can easily change the aspect ratio of your slides from Standard to Widescreen:

1. Open a presentation that has the Standard (4:3) aspect ratio, as shown in Figure 8.
2. 
   Figure 8: Standard size slide
2. Now, access the Design tab of the Ribbon, and locate the Slide Size button, as shown highlighted in blue within Figure 3 (scroll up this page).
3. Click the Slide Size button to bring up a drop-down gallery, as shown in Figure 9. Within this gallery, choose the Widescreen (16:9) slide size for your presentation.
4. 
   Figure 9: Widescreen (16:9) option within Slide Size drop-down gallery
4. Figure 10, shows the presentation's aspect ratio has now changed to Widescreen (16:9). Compare Figures 8 and 10.
5. 
   Figure 10: Standard size slide changed to Widescreen size
5. Make sure you save your presentation.