Merge PDFs
Combine several PDFs into one, in the order you choose. Pages are copied rather than re-rendered, so text stays text.
Drop two or more PDFs here. They merge in the order below.
Your files are processed on this device. Nothing is uploaded.
What merging actually does
A PDF is a collection of objects with an index saying which ones make up which page. Merging builds a new index that references the pages of both documents and copies the objects those pages depend on across. The content of a page is untouched: the same compressed streams, the same embedded fonts, the same images.
That is why the output is usually close to the inputs added up and why nothing gets blurrier. If a tool tells you merging will compress your document, it is doing something else as well.
Order is the part that goes wrong
Selecting ten files in a folder doesn’t mean they arrive in the order you see on screen. Sorting is up to the operating system and the file picker and it frequently differs from the sort order of the window you picked them from, especially where names contain numbers: page10.pdf commonly sorts before page2.pdf.
The list here shows the real order with page counts beside each file, so a misordered set is visible before you merge rather than after.
After merging
If the result needs pages removed, turned or shuffled, those are separate tools:delete pages,rotate pages andreorder pages. All three work the same way, on the document structure rather than on the rendered page.
Common questions
Are my PDFs uploaded anywhere?
No. Both the reading and the writing happen in this tab, using a PDF library compiled to run in a browser. That matters more for PDFs than for photos, because the documents people merge are usually contracts, invoices, medical records and scans of identity documents.
Does merging reduce quality?
No. Pages are copied from one document into another along with their content streams and embedded fonts, so nothing is re-rendered or re-compressed. Text stays selectable, vectors stay sharp and an image inside a page is the same image afterwards.
How do I control the order?
The list under the drop zone is the order and the arrows move a file up or down. File pickers return files in whatever order the operating system felt like, which is often alphabetical and rarely what you want, so it is worth checking before you merge.
Why will my PDF not open here?
Almost always a password. An encrypted PDF can’t be read without its password and this tool doesn’t ask for one, so it reports the file as protected rather than failing silently. Remove the password in whatever application made the file, then merge.
Is there a limit on size or number of files?
No imposed limit, because nothing is uploaded, so there is no upload cap to hit. The practical limit is memory: every document has to be held in the tab at once, so a hundred large scans on an old phone may struggle where a desktop won’t notice.
Guides
The other tools
All of them work the same way: the file is read in your browser and never uploaded.