Fix PDF Merge Combining Different Page Sizes — A4 and Letter Mixed
When merging PDFs with different page sizes, the result can have inconsistent sizes or squashed content. Here's how to merge cleanly and standardise page sizes.
Merging PDFs from different sources — A4 documents from European colleagues, US Letter from American ones, mixed portrait and landscape — gives you a combined PDF with inconsistent page dimensions. This causes layout issues when printing and looks unprofessional for shared documents. Here's how to handle it.
How Merge Tools Handle Different Page Sizes
Most PDF merge tools, including FixMyPDF's merge tool, preserve each source PDF's page size by default. An A4 page stays A4, a Letter page stays Letter — all merged into one file. This is correct behaviour for preserving original layout. The resulting PDF will have varying page sizes, which most viewers handle fine (each page shows at its own dimensions) but which can cause issues when printing on a fixed paper size.
Fix 1 — Standardise Page Sizes Before Merging
For the cleanest result, standardise all PDFs to the same page size before merging. Use FixMyPDF's resize tool on each PDF to convert to a common size (A4 if distributing in Europe, Letter if in the US). Then merge the standardised files. The merge output will have consistent dimensions. Content from smaller pages (Letter on A4 canvas) is centred with appropriate margins; content from larger pages is scaled down to fit.
Fix 2 — Resize After Merging
Alternatively, merge first and resize the combined PDF afterwards. This is faster when merging many files — merge all at once with FixMyPDF's merge tool, then pass the merged PDF through FixMyPDF's resize tool selecting "A4" or "US Letter" as the target. All pages in the combined PDF will be standardised to the same dimensions. Check the output to ensure no content was cropped on the larger pages after scaling.
When Mixed Page Sizes Are Intentional
For professional documents (annual reports, proposals) where some pages are intentionally landscape (charts, timelines) and the rest are portrait, mixed page sizes are appropriate. Viewers like Adobe Reader and Chrome handle mixed-size PDFs correctly — each page fits to the viewer window. For printing: use your printer's "Auto-rotate and centre" option which correctly handles mixed orientations. The key is that landscape pages are actually landscape (different dimensions), not just portrait pages with rotated content.
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