PowerPoint starts new presentations in landscape orientation because most slides are shown on screens. If you are making a poster, handout, social graphic, or tall layout, you can switch the deck to portrait from Slide Size.
Does this affect you?
Use this for PowerPoint for Microsoft 365, PowerPoint 2021, and PowerPoint 2019 on Windows or Mac. The important limitation is that slide orientation is applied to the entire presentation, not one slide at a time.
Switch the presentation to portrait
This changes every slide in the current file.
- Open the Design tab.
- Click Slide Size near the right side of the ribbon.
- Choose Custom Slide Size.
- Under Orientation, set Slides to Portrait.
- Click OK.
- When PowerPoint asks how to scale existing content, choose Maximize or Ensure Fit.
Maximize keeps objects larger but may push content past the slide edges. Ensure Fit shrinks objects so they fit inside the new shape, though you may still need to clean up spacing.
Clean up the converted slides
A deck designed for wide slides rarely becomes a polished tall layout automatically. Review every slide after changing orientation. Resize images, move text boxes, check placeholders, and make sure nothing important sits outside the slide boundary.
More control
Use a custom poster size
For printed posters, go to Design > Slide Size > Custom Slide Size and enter the exact width and height your printer or print shop recommends. Set portrait orientation at the same time.
Understand mixed-orientation limits
Standard PowerPoint does not truly mix landscape and portrait slides in one presentation. Pasted slides take on the orientation of the destination deck. The practical workaround is to keep separate landscape and portrait files, then link between them or export separate handouts.
Switch back to landscape
Repeat Design > Slide Size > Custom Slide Size and choose Landscape. PowerPoint will ask again whether to Maximize or Ensure Fit, and manual cleanup may be needed again.
Choose the scaling option carefully
For an existing deck, Ensure Fit is usually safer because it keeps objects visible. For a new file with little content, Maximize may be fine because there is less to repair.
Sources
- Microsoft Support – Change the orientation of a slide, from landscape to portrait or vice versa (2025)
- Microsoft Support – Change the size of your slides (2024)
- Microsoft Support – Use different slide sizes in the same presentation (2024)