When You Need to Merge PDFs with Different Page Sizes
It's common to encounter mixed page sizes when compiling work or academic materials.
- Combining an A4 report with A3 diagrams into one PDF
- Merging portrait text documents with landscape slides
- Mixing letter-size (US) and A4 (international) pages
- Scanned PDFs that differ slightly in size from digitally created PDFs
In these cases, you might worry: "Will merging force all pages to the same size?"
PDFnite Preserves Original Page Sizes
PDFnite's merge tool preserves the original size of each page. A4 pages stay A4, A3 pages stay A3 — all combined into one PDF.
This is possible because the PDF format itself allows pages of different sizes within the same file. PDFnite respects this specification and never forces pages to be resized.
In short, mixed portrait and landscape pages merge without any layout issues.
How to Merge with PDFnite
- Open the Merge PDF page
- Drag and drop all your PDFs — different sizes are fine
- Confirm the order (drag to reorder if needed)
- Click the "Merge PDF" button
- Download the merged PDF
All processing happens in your browser. Files are never sent to a server, so even confidential business documents are safe to use.
If You Want to Standardize Page Sizes
Sometimes you may want uniform page sizes in the merged PDF — for example, if you need everything to print on A4 paper.
Method: Re-export Using the Print Function
- Open the merged PDF in a browser or PDF viewer
- Go to "Print" → "Save as PDF"
- Set paper size to A4
- Enable "Fit to page" or "Scale to fit"
- Save as PDF
This will scale A3 or letter-size pages down (or up) to A4. Note that scaling down will make text and images smaller.
Things to Know About Mixed-Size Merging
- For screen viewing, mixed sizes are fine: PDF viewers automatically adjust to each page's size
- For printing, check your printer's paper settings: For mixed-size PDFs, selecting "Fit to paper size" in your printer settings is recommended
- Scanned PDFs may have slight size variations: Scanner settings can result in pages that aren't exactly A4, but this doesn't affect merging
Frequently Asked Questions
Will pages be scaled up or down during merging?
No. PDFnite's merge tool preserves the original size of every page. No automatic resizing occurs.
Can I mix portrait and landscape pages?
Yes. Portrait and landscape pages can coexist in the same merged PDF, with each orientation preserved.
Will margins or content change after merging?
No. The merge process makes no changes to page content or margins. The original PDFs are concatenated exactly as-is.
Can I merge PDFs with different image resolutions?
Yes. In PDF format, resolution is a property of individual images rather than the overall page. Merging files with different resolutions has no impact on quality.
Summary
For merging PDFs with different page sizes, PDFnite preserves each page's original size without any forced resizing. Mixed A4, A3, letter, portrait, and landscape pages all merge without issue. It's free and requires no installation — try it at Merge PDF.