How to Change Slide Size in PowerPoint (2026)
Slide size sets the aspect ratio and dimensions of your whole deck. The two presets are Widescreen (16:9), the modern default, and Standard (4:3) for older projectors — plus a Custom option for exact inches or pixels. Changing it triggers a scaling choice that affects how your existing content fits. Here’s the full control.
1. Switch Between 16:9 and 4:3 (Windows & Mac)
- Go to the Design tab.
- Click Slide Size.
- Choose Standard (4:3) or Widescreen (16:9).
If the deck already has content, PowerPoint asks how to scale it (see section 3).
2. Set a Custom Slide Size
- Design > Slide Size > Custom Slide Size.
- Pick from the Slides sized for presets (A4, Letter, On-screen Show, Banner, etc.), or type exact Width and Height.
- Set the Orientation to Portrait or Landscape.
- Click OK.
This is how you make a poster, A4 handout, or portrait deck.
3. Maximize vs. Ensure Fit
When you change size with content present, PowerPoint asks:
- Maximize — scales content up to fill the new size (may crop edges).
- Ensure Fit — scales content down so everything stays visible (may leave margins).
Choose Ensure Fit when you can’t risk cutting anything off.
4. Change Slide Size on the Web
In PowerPoint for the web, open the Design tab and click Slide Size, then pick Standard (4:3) or Widescreen (16:9). Custom dimensions are a desktop feature.
5. Set Orientation to Portrait
In Custom Slide Size, set Orientation > Slides to Portrait. Note that a deck uses one orientation throughout — PowerPoint can’t mix portrait and landscape slides in the same file.
6. Troubleshooting
My content looks stretched after resizing
You picked Maximize. Undo with Ctrl+Z and choose Ensure Fit instead.
Some elements got cut off
Maximize cropped the edges. Reapply the size with Ensure Fit, then nudge any stray elements back on-slide.
I need portrait and landscape together
One file is one orientation. Build two decks (one each) and link or merge them when presenting.
Related PowerPoint guides: How to add slide numbers · How to add a footer · How to make a timeline · How to insert a table · How to group objects
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