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How to Merge PDF Files (and Keep Them in Order)

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One attachment beats five. Merging PDFs takes under a minute. The part worth thinking about is order, and what to do when the combined file gets big.

The one-minute answer

Open Merge PDF, drop in your documents, arrange them with the arrows (top file = first pages), click Merge PDFs, download. Pages are copied exactly (no re-compression, no quality change) and the merging happens in your browser, so contracts never leave your device.

Getting the order right

The file list is your table of contents. Cover letter above the CV, contract above its annexes, chapters in sequence: rearrange with the up/down arrows until the list reads the way the final document should. Nothing is fixed until you click Merge; add and remove freely while you decide.

Mixed sizes, orientations, and sources

A4 with Letter, portrait with landscape, a phone scan with a Word export: all fine. Each page keeps its own dimensions and rotation in the merged file. If some pages are photos of paper, consider building them into a clean PDF first with JPG to PDF so page sizes come out uniform.

After the merge

What doesn't survive a merge

Document-level extras (bookmarks, outlines, form-field logic that spans documents) don't carry over; page content does, exactly. Password-protected files need their password removed before merging, since an encrypted document can't be read at all.

Why the merged file is bigger than the parts

Sometimes a merged PDF is larger than the sum of its inputs. Each source document carries its own copies of fonts, colour profiles, and images, and a merge copies pages faithfully rather than deduplicating what they share, so three exports from the same template can bring three copies of the same font. That is normal, and the fix is the same as for any oversized PDF: run the result through the PDF Compressor once, after merging, rather than compressing each part first and then merging.

Merging photos, scans, and PDFs together

A merge tool takes PDFs only. If some of your pages are photos of paper, receipts, or screenshots, turn them into a PDF first with JPG to PDF or PNG to PDF, choosing a page size so they match the rest, and then merge that PDF with the others. Doing it in that order also gives you control of the image pages' order and orientation before they are locked into the combined file.

On a phone

The merge tool runs in the browser, so it works the same on a phone as on a laptop: open the page in Safari or Chrome, tap to choose files from your photos or file manager, arrange them, merge, and the combined PDF goes to your downloads. Nothing is uploaded on either device. Large scans take longer on a phone, but the result is identical.

Common questions

Does merging PDFs reduce quality?
No. Pages are copied as they are, without re-rendering or re-compressing, so text stays sharp and images keep their original resolution. Only a compression step, if you choose to run one afterwards, changes quality.
Can I merge password-protected PDFs?
Not while they are encrypted. Open the file with its password in a PDF viewer, save an unprotected copy, and merge that. The merged output is not protected; add a password afterwards if you need one.
Is there a limit on how many PDFs I can merge?
There is no fixed count. The practical limit is your device's memory, since everything happens in the browser. Dozens of ordinary documents are fine; very large scanned files are the ones that push a phone.
How do I change the page order after merging?
Split the merged file into the pages you need with Split PDF, then merge them again in the new order. Together the two tools rearrange, remove, and combine pages without any other software.

Try it yourself

These live under PDF tools, alongside the rest of the pdf documents & workflows guides on the guides page.

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