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Match the presentation environment
Use 16:9 for most modern displays and meetings. Choose 4:3 for older projectors or templates. Source ratio follows the first selected PDF page.
Fit preserves; fill crops
Fit shows every edge and uses background space when proportions differ. Fill removes letterboxing by cropping edges. Stretch fills the slide but changes proportions.
Review mixed page sizes
A presentation uses one slide size. When a PDF mixes portrait and landscape pages, inspect every preview and choose the safest framing.
Put the workflow into practice
Arrange source documents, select the pages you need, and create one PDF locally in your browser. Review the result before choosing any optional next step.
Try Merge PDFFrequently asked questions
Clear answers before you merge
Is 16:9 always best?
It is common, but the venue may require another ratio.
Does Fill slide lose content?
It can crop edges when proportions differ.
What does Source ratio use?
The first selected PDF page proportions.
Can slides have different sizes?
PowerPoint uses one shared slide size.
