Merge PDF
Combine several PDF files into one document. Runs on your device — the files are never uploaded.
Processed on your device — no upload
How to merge PDF
- Choose the PDF files you want to combine. Add as many as you need.
- Put them in the right order using the arrows — the list order is the page order.
- Press Merge. The combined PDF downloads straight to your device.
How it works
A PDF is not really a stream of pages: it is a small database of objects — fonts, images, text blocks — with a cross-reference table that says where each object lives in the file. Merging two PDFs means copying the objects from one document into another, renumbering them so nothing collides, and writing a fresh cross-reference table.
This page does that work inside your browser tab. When you pick a file, JavaScript reads it into memory with the standard File API, parses the object tree, copies each page into a new empty document, and serialises the result back into PDF bytes. The finished file is handed to your browser as a download.
Nothing is transmitted. There is no upload step because there is no server to upload to — this site is a set of static files, and the merging code runs on your processor. You can prove it: open your browser's developer tools, switch to the Network tab, and merge a file. You will see no request carrying your document. You can also disconnect from the internet entirely after the page loads and the tool still works.
Because the page objects are copied rather than re-encoded, the merge is lossless. Text stays selectable, images keep their original resolution, and a 4 MB input does not come back as a blurry 400 KB output.
A worked example
Say you are submitting an expense claim and you have three separate scans: hotel.pdf (2 pages), taxi.pdf (1 page) and dinner.pdf (1 page). The finance team wants one file.
Choose all three at once. They appear in the order the file picker returned them — probably alphabetical, which would put dinner first. Use the ↑ arrow to move hotel.pdf to position 01, so the claim reads in the order the expenses happened.
Press Merge 3 files. The status line reports the total, and merged.pdf lands in your downloads folder with 4 pages: hotel pages 1–2, then the taxi receipt, then dinner. Total time on a mid-range laptop for files of this size: well under a second.
A detail worth knowing: if one of those scans was produced by a phone scanning app, it may carry a rotation flag. The merge preserves that flag rather than silently flattening it — so if a page looks sideways afterwards, it looked sideways before, and the rotate tool will fix it in one step.
Questions
Is this the same as combining or joining PDFs?
Yes. Merge, combine, join and concatenate all name the same operation: several documents in, one document out, pages in the order you set.
How do I append one PDF to the end of another?
Put the second file below the first in the list. The list order is the page order, so appending is simply adding it last.
Are my files uploaded anywhere?
No. The merging code runs in your browser using JavaScript. There is no server component to this site at all — it is static files on a CDN — so your document never leaves your device. You can verify this in the Network tab of your browser developer tools, or by going offline after the page loads.
Is there a file size limit?
There is no limit imposed by us, but there is a practical one set by your device memory, because the whole document is held in RAM while it is processed. On a typical laptop, merging files totalling a few hundred megabytes is fine. On an older phone you may want to stay under about 100 MB.
How many PDFs can I merge at once?
As many as you like. The tool processes them one after another, so the constraint is total size rather than file count. Merging 50 single-page documents is no harder than merging two large ones.
Does merging reduce the quality of my PDF?
No. Pages are copied object by object rather than re-rendered or re-compressed, so text stays as text, images keep their original resolution, and the output is visually identical to the inputs.
Can I merge a password-protected PDF?
Not while it is still encrypted. If a file is password-protected the tool will tell you which one it is. Open it in your PDF reader, save an unprotected copy, then merge that copy.
Can I change the order of the pages after merging?
The merge itself follows the order of the file list, which you control with the arrow buttons. If you need to reorder or drop individual pages afterwards, use the delete pages tool on the merged file.
Does it work on a phone?
Yes. Tap the file area to open your phone file picker, choose your PDFs, and the merged file is saved through your normal download flow. Very large documents are limited by phone memory more than by anything else.
Do I need an account, and is it really free?
No account, no email, no watermark and no page limit. Since the work happens on your device rather than on rented servers, running this tool costs us nothing per use.
Is combine PDF the same as merge PDF?
It is the same operation under a different verb. Combine PDF, join PDF, append and concatenate all describe what this page does: several PDFs in, one out, pages in the order you set. If you arrived looking to combine PDF files or join PDF files, you are in the right place.
How many PDFs can I merge at once?
As many as you like — merge PDFs two at a time or twenty in one pass. The limit is total size rather than file count, because they are processed one after another, so combining fifty single-page PDFs is easier on memory than combining two large ones.
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