Merge PDF
Combine several PDFs into one document in the order you choose. Page content, images and embedded fonts are copied unchanged.
Tool workspace
Nothing is uploaded. Files are read in this tab and stay on your machine.
Combine PDFs into one document
Save your download before you leave the page — it exists only in this tab.
How do I merge PDF files?
Select the PDFs you want to combine. They are combined in the order listed; use Move up and Move down to change it.
Check the page count shown for each file. If a file was damaged and had to be repaired, the list says so.
Select Combine, then save the result before leaving the page.
How does merging keep every page unchanged?
Merge PDF files into one document, in the order you set with Move up and Move down. Each page is copied with its content, images and embedded fonts exactly as they were, so combining PDF files here re-encodes nothing and loses no quality.
To merge PDF files without altering them, the tool copies objects rather than redrawing pages. A PDF is built from linked parts: pages, the drawing instructions for each page, images and fonts. Combining documents means copying those parts into a new file and building a new list of pages over them. Because each page’s drawing instructions are copied with their bytes and their compression untouched, there is no decode and re-encode step in which a page could be degraded. Settings a page took from the document around it, such as its size, are written onto the page itself so they survive when the old list of pages is replaced. That is how a covering letter, a specification and a set of drawings become one file for a transmittal. A combined drawing set can then be opened in Xenmark for reviewers to mark up and comment on.
How Xenmark makes it easy to merge your PDF files
One document, in the order you chose
Put the files in the order you want with Move up and Move down, and they come out that way. Nothing is re-sorted, renamed or reflowed on the way through.
Nothing leaves your machine
Nothing is uploaded. Files are read in this tab and processed in memory, with no account and no server for them to go to.
Pages copied, not re-encoded
Every page keeps its drawing instructions, images and fonts byte for byte. There is no decode step in which quality could be lost.
Page counts before you commit
Each file shows its page count as soon as it is read, so a wrong or damaged file is visible before anything is combined.
Honest about what it drops
Bookmarks and form fields point at pages in their old document and are not remapped. The tool tells you which were present rather than losing them silently.
Damaged files are rebuilt, and you are told
A PDF whose internal index is broken is recovered by reading through the file for its parts, and the list marks it so you know it happened.
Limitations
What this tool does not do, stated up front.
Bookmarks, named destinations, page labels, tagged structure, form-field definitions, file attachments, layer settings and document properties are not carried across. The tool lists which of these were present. Settings that belong to a whole document — the reading language, and how a reader opens and lays out the file — are taken from the first file, and the tool says so when a later file set them differently.
Encrypted documents are refused rather than partly read, even ones that open without a password, because acting on a document whose protection state is unknown risks producing an unprotected copy.
Up to 32 PDFs, each up to 64 MiB, can be combined, and the combined file holds at most 5,000 pages.
Questions
Does merging PDFs reduce quality?
No. Page content, images and embedded fonts are copied byte for byte with their existing compression, so there is no step at which quality could be lost.
Can I change the order?
Yes. Files are combined in the order the list shows. Use Move up and Move down beside each file to change it before you select Combine.
How many PDFs can I merge at once?
Up to 32 files at a time, each up to 64 MiB, and the merged document can hold up to 5,000 pages.
Why did Xenmark build a free merge tool?
Xenmark AS is a Norwegian software company building browser-based drawing review tools for owners, consultants, operators and other teams that receive and review technical drawings. Those teams handle PDFs every day, and not every file should be sent to a website just to merge, split or check it — a tender document, a client’s drawing set, a revision that is not released yet. So these everyday tools are free and run entirely in your browser: no account, no upload step, and no server ever receives the file. You can check that yourself — open your browser’s network tab, merge something, and watch nothing leave. What this tool cannot do is listed under Limitations above.
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Reviewing the drawings, not just handling the files?
Xenmark is affordable PDF markup and structured drawing review in the browser. Invite reviewers, pin numbered comments on the sheet, track every one by author and status, and export a clean PDF and Excel when the review is done. Unlike these tools, a review is shared, so its drawings are uploaded to your Xenmark project.
Free forever plan. Reviewers you invite never pay.