About merge PDF
Merging is the most common PDF task and also the one most often done in the least private way — uploading a stack of contracts or statements to a stranger's server to perform an operation that is really just concatenation. Combining PDFs does not require a server at all. Each page in your source files is an object that can be copied wholesale into a new document, which is exactly what this tool does inside the page you are reading. Because the page objects are copied rather than re-rendered, the result is lossless: selectable text stays selectable, embedded fonts come along, and image quality is untouched. Output size depends on the source structure and how the new document is saved. This is not a compression tool: identical resources from separate input files are not automatically deduplicated, so the result may be larger or smaller than their combined size.
How to merge PDF
- 01
Add your PDFs
Drop two or more files onto the drop zone, or use Choose files. You can add more before starting the merge, within the file and memory limits.
- 02
Put them in order
Use the arrow buttons beside each file to rearrange the list. They work with a mouse, touch or keyboard. The list top-to-bottom is the page order in the result.
- 03
Merge
Press Merge PDF. The work happens on your own device, so speed depends on your machine, not a queue.
- 04
Download
Download the combined document before closing the tab. File contents are not uploaded; closing the tab discards the working copy, but does not delete files you already downloaded.
What this tool does
- Merge up to 250 files within the 250 MB per-file and 600 MB total input limits; available memory may impose a lower practical limit
- Arrow-button reordering with mouse, touch and keyboard support
- Lossless page copying: no re-compression of text or images
- Optional flat bookmark list with one entry per source file; existing source outlines are not preserved
- Optional blank-page insertion so each file starts on a right-hand page
Limitations worth knowing
Every PDF tool has constraints. Stating them plainly is more useful than discovering them halfway through your work.
- Encrypted PDFs are rejected. Use an authorized application that can decrypt the file, then select an unencrypted copy; this page has no password prompt.
- Interactive form structure and values are not guaranteed to survive page copying. Flatten forms in a capable PDF editor first if their visible values must be preserved.
- Digital signatures are invalidated by merging — this is inherent to changing a signed document, not a limitation of this tool.
- Each input PDF is limited to 5,000 pages. Large merges can still exhaust browser memory below the file-size and file-count limits.
How your file is handled
This tool runs entirely inside this browser tab. When you choose a file, your browser reads it from your own disk and hands the bytes to JavaScript running on this page — no network request carries your document anywhere. You can confirm that yourself: open your browser’s developer tools, switch to the Network panel, and run the tool. You will see no upload.
Nothing is stored after the fact. Closing or reloading this tab discards the file, the result and everything derived from them, because none of it ever left your machine. Read how local processing works.
Questions about merge PDF
Is there a limit on how many PDFs I can merge?
Yes. One selection can contain up to 250 files, with a 250 MB limit per file and 600 MB total. Each input PDF is also limited to 5,000 pages. Processing uses browser memory, so a large or image-heavy selection can exceed your device capacity even below those limits.
Are my files uploaded to a server?
No. The merge runs entirely in your browser tab using a local PDF library. No request carrying file content is made, which you can confirm in your browser's network inspector.
Will merging reduce quality or make text unselectable?
No. Pages are copied as objects, not re-rendered or re-compressed, so text remains selectable and searchable and images keep their original data.
Will the merged file be smaller than the sum of the originals?
Not necessarily. The new document uses a different object structure and saving settings, so its size can increase or decrease. Identical fonts or images from separate input files are not automatically deduplicated. Merging preserves page content; it does not promise compression.
Can I merge a password-protected PDF?
Not directly. This merge tool rejects encrypted PDFs and does not ask for a password or decrypt them. If you have permission, open the PDF in an application that supports decryption, save an unencrypted copy, and merge that copy here.
Tools that pair with this one
- Combine PDFAssemble a set of PDFs into one file, arranged the way you want.
- Split PDFCut one PDF into several documents — by range, by interval or page by page.
- Compress PDFMake a PDF smaller by re-encoding its images and cleaning up its internals.
- Organize PDFPut the pages of your document in the order you actually want.
- Rotate PDFTurn sideways or upside-down pages the right way up, permanently.
- Extract PDF PagesKeep only the pages you want and leave the original untouched.
Read more about this
- How to merge PDF filesJoining documents copies pages into a new PDF rather than re-rendering them. This guide covers the actual order controls and the document-level features that a merge cannot promise to preserve.5 min guide
- How to split a PDF into separate filesSplitting turns one document into many. This guide explains the three split methods, how to pick between them, and what each output does and does not inherit.5 min guide
- How to delete pages from a PDFDeleting pages rebuilds the document from the pages you kept. Lossless for the survivors, and not the size fix people expect it to be.4 min guide