1Upload every file you want combined — at least two of them.
2Drag the uploaded items into the order you want; the order is taken from the list, not from the filenames.
3Start the merge, which joins matching inputs without re-encoding them and reconciles mismatched ones exactly once.
4Download the single combined PDF file.
Merge PDF FAQ
Anything specific to PDF when merging?
+
Yes — a PDF is an object graph, not a page image, so text stays selectable and vectors stay sharp no matter what happens to the raster content inside it. That is worth checking when the inputs did not all come from the same source.
Is the merge lossless?
+
It is whenever the inputs already agree — the encoded data is copied straight through. It stops being lossless only when the inputs disagree and something has to be re-encoded to make them compatible, and even then it is one pass, not one per file.
How does Merge PDF join the files together?
+
Concretely, the page trees are appended into one document, so text stays selectable, bookmarks are merged into a single outline and nothing is rasterised anywhere in the process. Upload everything you want combined and the result comes back as a single file.
Can I control the order things are joined in?
+
Yes — drag the uploaded items into the order you want before starting. Order is taken from the list, not from the filenames, so "IMG_2.jpg" sorting after "IMG_10.jpg" is not a problem you have to solve first.
Does Merge PDF cost anything?
+
No. Merge PDF is free without an account, and nothing is stamped onto the pages. Uploaded documents are deleted from the workers shortly after the job completes.
What can I upload to Merge PDF?
+
Any standard PDF, including ones produced by a scanner, by a word processor or by a print driver. Files with an owner password that only restricts editing are handled; files that need a user password to open are not, and we do not attempt to break encryption.
Is there a file size limit on Merge PDF?
+
Yes: free accounts process documents up to 25 MB each, which covers most reports and contracts but not a long scanned document at 600 DPI; Ghostscript and qpdf do the work. Scanned PDFs are the usual thing that exceeds it, and compressing the document first is normally enough to bring it back under.
Do bookmarks, links and form fields survive?
+
Outlines, internal links and annotations are preserved wherever the operation allows it. Digital signatures are the exception: any change to the file necessarily invalidates a signature, because that is precisely what a signature is for.
Why does a MP3 site host Merge PDF?
+
MP3.to is built around the format that made portable audio ordinary: universally playable, small enough to ignore, and lossy in a way that only matters if you keep re-encoding it. Audio jobs cluster: the same person who needs a format changed usually needs the file cut, levelled or made smaller in the same sitting. Putting Merge PDF behind the same upload, the same caps and the same account is what turns three tabs into one.
What should I do with the result once Merge PDF is finished?
+
The converter on this site moves audio between MP3, WAV, FLAC, M4A, OGG and Opus, so the output format is a decision you can leave until the end rather than commit to at the start. Doing that after Merge PDF rather than before means the encode happens once, on the file you actually settled on, instead of twice.
Is Merge PDF here the same tool the sibling sites run?
+
The engines are shared — the same ffmpeg build, the same workers, the same limits. What a MP3 site adds is a point of view about bitrates, about what survives an encode and about when a lossless intermediate is worth the upload time. It also starts from one fact about the format this site is named after: MP3 frames are fixed-size blocks, so a cut lands on a frame boundary and gapless playback markers do not survive a re-encode.
Do I need an account, and does anything get kept?
+
No account, and nothing is kept: uploads are deleted from the workers shortly after the job finishes, nothing is listened to and nothing is indexed. Free accounts exist for history and batch size, not for access.
