Start with the merge requirements
Add two or more .pdf files. The Merge PDFs button becomes available only when at least two files can be included. Processing happens in your browser, and the original source files are not modified.
Add, check, and arrange files
Files appear in the numbered list in their current merge order. Drag an eligible row, or use Move up and Move down, to change that order. Use Remove to take a file out.
- Files that are not
.pdfare skipped when selected through the file input. - Unreadable or unparsable PDFs are blocked and reported. Encrypted or password-protected PDFs are also blocked and excluded.
- Blocked files cannot be reordered or included. Remove them and add a readable, unencrypted PDF if needed.
Choose Pages and bookmarks
Leave Pages blank to include all pages from that file. To select specific pages, enter comma-separated, one-based page numbers and ranges such as 2,4,7-9.
Invalid or out-of-range fragments are ignored. Descending ranges are read in ascending order, duplicate pages are removed, and the selected pages stay in source-page order.
When bookmarks are enabled, the tool adds one flat bookmark for each included file with selected pages. Titles start as filenames and can be edited. Source outline trees are not copied.
Preview, merge, and review the result
The preview renders automatically in final merge order and shows at most the first 150 selected pages; the merge still includes every selected page beyond that cap. If an individual page cannot render, its preview card reports a render failure without changing the merge plan.
Click Merge PDFs, review the Merge report, then use Download merged.pdf. The report lists included pages, excluded files, signature and XFA warnings, and bookmark creation.
Preserved properties and file warnings
Pages are copied as PDF page objects, so each page keeps its source page size and rotation. Mixed page sizes and orientations can remain in the output.
- Encrypted / password-protected files are detected and excluded. The tool does not decrypt or unlock them.
- Malformed / unparsable files are blocked, excluded, and reported.
- Digitally signed files may be included, but copying their pages into a new document invalidates the source signature.
- XFA files may be included with a warning; their form interactivity is not preserved.
The tool does not rasterize pages or strip protection to make a file merge.
How to merge PDFs
- Drop or browse for two or more .pdf files.
- Arrange eligible files with drag-and-drop, Move up, or Move down. Use Remove for files you do not want.
- Set Pages for any file that needs a partial selection.
- Configure optional bookmarks and edit their titles.
- Review the automatic page preview, then click Merge PDFs.
- Review the Merge report and download merged.pdf.
Privacy and processing limits
Files are parsed and merged locally in the browser using pdf-lib and pdfjs-dist; nothing is sent to a server. The implementation defines no fixed maximum file count or total merged-page limit. Preview rendering is capped at 150 selected pages, while larger jobs may depend on browser memory and processing performance.
Frequently asked questions
Can this tool merge password-protected PDFs?
No. Encrypted or password-protected PDFs are detected and excluded from the merge - this tool never attempts to unlock, guess, or remove a password. Remove the password with the file's owner or a dedicated unlock tool first, then merge.
What happens to bookmarks and outlines from the source PDFs?
Each source PDF's original outline tree is not carried over - pdf-lib cannot reliably copy an arbitrary nested outline across documents while remapping destinations. Instead, if you enable bookmarks, this tool adds one flat, top-level bookmark for each included file with selected pages, pointing at that file's first merged page.
Are page size and rotation preserved?
Yes. Pages are copied as PDF page objects, not re-rendered, so each page keeps its original media box size and rotation value from the source file - mixed page sizes and orientations in one merged PDF are expected and supported.
What about digitally signed or malformed PDFs?
Digitally signed PDFs can still be merged, but you're warned first: copying pages into a new document invalidates the source's cryptographic signature, so the output is not signed. Malformed PDFs that fail to parse are excluded and reported rather than guessed at or rasterized.
Does it upload my files anywhere?
No. Files are parsed and merged entirely in your browser using pdf-lib and pdfjs-dist. Nothing is sent to a server, and your original source files are never modified.