Merge PDF files online for free
Drop two or more PDFs here, or click to browse
Your files never leave your browser
Merging PDFs is one of the most common document tasks — combining scanned pages, joining chapters, or assembling a single application packet from several forms. This tool runs entirely in your browser using pdf-lib, so your files are never uploaded anywhere. Add as many PDFs as you need, use the up/down arrows to set the order, and download a single combined file. Because everything happens locally, there's no file size limit imposed by a server, only by your device's available memory.
Order matters more than people expect
The single most common mistake when combining documents is uploading files in whatever order the file picker returned them, which is usually alphabetical rather than logical. A set of scans named page1, page10, page2 will sort in exactly that unhelpful order. Use the up and down arrows to set the sequence explicitly before merging, and check the first and last file in the list — those are the two positions people most often get wrong, because attention drifts to the middle of a long list.
Merging does not re-compress anything
Pages are copied from each source document into the new one without being re-encoded, so a merged file is roughly the sum of its inputs and the quality is identical to the originals. That is usually what you want, but it does mean merging ten large scans produces one very large PDF. If the combined file needs to fit an upload limit, merge first and compress afterwards, in that order — compressing each part separately and then merging tends to give a worse result for the same final size.
What this tool cannot open
Password-protected PDFs will not merge, because the file's contents are encrypted and cannot be read without the password. You will need to unlock the document first using whatever application created it or a dedicated unlock tool. Damaged or partially downloaded PDFs will also fail; if a file opens with errors in your normal PDF reader, it will not merge cleanly here either.
Frequently asked questions
- How many PDFs can I merge at once?
- There's no fixed limit — you're only bound by your browser's available memory, which comfortably handles dozens of typical documents.
- Can I reorder files before merging?
- Yes, use the up and down arrows next to each file to set the order; the output follows that order.
- Are my files uploaded to a server?
- No, merging happens locally in your browser. Nothing is sent anywhere.
- Does merging affect PDF quality?
- No, pages are combined as-is with no re-encoding, so quality is identical to the source files.
- Can I merge password-protected PDFs?
- You'll need to unlock a password-protected PDF first — this tool doesn't handle encrypted files.
- Will merging change the page size or orientation?
- No. Each page keeps its own dimensions and rotation, so mixing A4 portrait pages with landscape scans produces a document where each page retains its original shape.
- Can I merge more than two files at once?
- Yes, add as many as you need in one pass. The practical limit is your device's memory rather than any fixed number.