Merge PDF Online
Combine multiple PDFs into one document. Files are processed in your browser.
Drop PDFs here
or choose files from your device
Copying pages, not reprinting them
Merge PDF loads pdf-lib 1.17.1, creates an empty document, and for each selected file calls copyPages on every page index. Those pages are appended in list order and saved in the browser. There is no canvas and no JPEG step. A 12-page text packet finishes in well under two seconds on a current laptop because the work is object copying. A few hundred megabytes of phone scans is a memory problem, not a format problem: every source is decoded together.
Input is application/pdf, including files whose names end in .pdf when the MIME type is empty. You need at least two files or the button stays disabled. Output is one PDF. Damaged xref tables fail the same way encryption does. Open each source alone before you blame the join.
| Piece | What this page does |
|---|---|
| Engine | pdf-lib copyPages in the tab |
| Upload | None. No PDFSwift file endpoint |
| Transport | The site is HTTPS. The PDF is not part of a request |
| Practical size | Tab memory. Roughly 150 MB combined on a phone |
Where a joined file is the actual deliverable
Closing set
Cover, agreement, disclosure, signature page. Prefix them 01 to 04 on disk, then confirm the list. Search the download for one rare phrase from each source. The seam between a native file and a scan should still look like both parents.
Monthly archive
Four weekly exports become one file for the folder, not for the mailbox. Keep that master uncompressed. If email rejects it, compress a sibling later. Merging does not shrink anything.
Mixed page sizes
A phone photo page next to A4 survives as mixed media boxes. Say so if someone will print. This page will not quietly scale everything to A4.
Context for a later question
Join the exhibits you actually need, then split the chapter you will ask about. A 200-page join is a bad prompt. The master can still exist.
From the drop zone to the download
- Drop two or more unlocked PDFs. The list shows each name and size.
- Read the list out loud. Delete a row if the sequence is wrong.
- Click Merge PDFs. The button stays off until two files are present.
- Save
pdfswift-merged.pdf. Check the page count against the sum, then highlight one sentence from the last file.
If text that used to select no longer selects, throw the export away. You reprinted somewhere else. Run this page again on the originals. Related notes: what a soft merge looks like and when to shrink afterwards.
What to count after the download
Add the page counts from each source before you click. The download’s page count should equal that sum. A missing page is a file that failed to load, not a page pdf-lib dropped on purpose. Open the first page of the second file in the result and compare a heading with the source. If the heading is there and selectable, the join worked. If the file opens but the status had thrown, you are looking at an older download in the same folder.
Frequently asked questions
Does a merge turn text into images?
No. The page creates an empty PDFDocument and copyPages from each file you added. Text that you can highlight in the source stays highlightable in the result. Soft pages mean a different tool, usually Compress, ran afterwards.
Why does merge fail on a password-protected file?
PDFDocument.load does not prompt for a password. Encrypted files throw, and the status line asks for a valid unlocked PDF. Unlock a copy you are allowed to open, then merge that copy.
Is there a maximum file size?
There is no server quota, because nothing is uploaded. The cap is the tab. Phones often stall somewhere around 150 MB of combined sources. An 8 GB desktop can hold more, and iOS Safari usually dies first. If “Merging…” sits for more than a minute, merge in two batches.
Do bookmarks and form fields survive?
The page objects move. The document outline is not rebuilt as a combined table of contents. Fields and annotations usually ride with the page, but test one field after export if someone still has to type into it.
Are the files stored?
No. The bytes stay in the tab, the download is named pdfswift-merged.pdf, and the Worker never sees the document. The site itself loads over HTTPS. That protects the page, not a copy of your PDF, because there is no copy.
What if the page order is wrong?
The on-screen list is the page order, not the alphabetical order on disk. Remove and re-add until the list matches the packet. Numeric prefixes only help if you add the files in that sequence.