How to Merge PDFs of Different Sizes? A4, A3 Mixed Merge Guide
Want to merge PDFs of different sizes? Learn how to handle merging PDFs with different page sizes like A4, A3, Letter while maintaining original layouts.
Can You Merge PDFs of Different Sizes?
Yes! PDFs with different page sizes can be merged into one file
A powerful feature of PDF format is that each page can have different dimensions. When merging, each page keeps its original size and won't be forced to a uniform size. This means you can confidently merge documents of different specifications like A4, A3, Letter, etc.
Common PDF Page Sizes
A4 (210×297mm)
International standard, most commonly used
Letter (216×279mm)
North American standard size
A3 (297×420mm)
Double the size of A4, for large charts
Custom sizes
PPT conversions, design drafts, etc.
All these different sized PDFs can be seamlessly merged into one file.
Results After Merging
Original Sizes Preserved
In the merged PDF, each page retains its original dimensions.
Example:
Page 1 is A4 (210×297mm), Page 2 is A3 (297×420mm), Page 3 is A4 again — totally fine!
Viewer Auto-Adapts
When viewing in a PDF reader, the software automatically adjusts display ratio so each page fits properly on screen. Users won't feel abrupt when turning pages.
Printing Considerations
When printing, pages of different sizes may require different paper or scaling settings. It's recommended to preview before printing and adjust as needed.
How to Merge?
- 1Open our PDF merge tool
- 2Upload all PDF files to merge (regardless of size)
- 3Arrange files in desired order
- 4Click merge, download the merged file
Practical Tips
- 💡Check before merging: Confirm each PDF's page orientation (landscape/portrait) is correct
- 💡Order planning: Group pages of same size together for easier printing later
- 💡Add cover page: Create a unified size cover page first
- 💡Compression optimization: If merged file is too large, use compression tool to reduce size