Merge PDF
Combine multiple PDFs into one file, put them in the order you want, and download the merged PDF. Your files stay in your browser.
Up to 30 PDFs · 50 MB total · 300 input pages total · output up to 50 MB
Your PDFs stay in your browser. Originals are not changed. No document upload or saved history.
How it works
- Add two or more PDFs. You can add more files later.
- Arrange document cards with Move up/down, or drag them on desktop.
- Open Organize pages only if you need to rearrange, rotate or remove individual pages.
- Click Merge PDFs, wait for local verification, then download the new file.
A real example
A fictional application has a three-page form, a two-page attachment and a one-page cover. Move the cover to the beginning. The merged PDF contains the cover, the form and then the attachment: six pages in that order.
Document order or individual page order
Normally, every page is combined in the order of the document cards. Add more PDFs using the same upload area; previous files stay in the list. Matching filenames and repeated copies are allowed, with separate document identities.
Organize pages opens a lazy thumbnail grid. Select pages across files to move, rotate or delete them. After the first page edit, that exact page sequence takes priority and document reordering is disabled. Newly added PDFs append their pages. Restore document order discards page edits and returns every source page to the document sequence.
Unreadable files remain clearly marked and block merging until removed. A file that exceeds a total limit is rejected with an explanation; existing files remain. At least two readable documents and one output page are required.
A new PDF, with local checks
Original files are never modified. Pages are copied using the existing PDF engine, rather than rebuilt from thumbnails. There is no intentional downsampling, image conversion or compression of page content.
The output is parsed again, and page count, rotations, page boxes and copied content streams are checked against the requested source order. PDF.js checks that the generated document opens. Only then does Download Merged PDF become available; merging does not force an automatic download.
Complex forms, digital signatures, bookmarks, annotations, accessibility tags and embedded document behavior may not survive page copying exactly. Digital signatures will not remain valid after merging. Review important output and keep the originals. This is not PDF repair or sanitization.
Private processing and practical limits
PDF bytes, filenames, page information, thumbnails and output remain in browser memory. They are not uploaded, placed in URLs, saved in localStorage or automatically included in feedback. PDF libraries and assets load from RST; no external document API is used.
Add up to 30 PDFs with a combined input limit of 50 MB and 300 pages. The output also has a 50 MB limit. Document cards show only the first page; other thumbnails render lazily when you open page organization. Large or complex files may take longer or exceed browser resources.
Remove a document to release its resources. Clear all or leave the page to clear the session. Password-protected PDFs must be unlocked in an authorized application first; this tool does not bypass or remove passwords.
Frequently asked questions
Are my PDFs uploaded?
No. Reading, thumbnails, merging and verification run locally. Documents and generated files are not uploaded or saved in browser storage. Established site requests still load the website; feedback does not automatically include file data.
How many PDFs can I merge?
Up to 30 files, with 50 MB and 300 input pages in total. The output must also fit within 50 MB. At least two readable documents are needed. You can intentionally add the same PDF twice.
Can I change the order before merging?
Yes. Move up/down works on phones and keyboards, and desktop cards support drag-and-drop. Every page follows the displayed document order unless you make individual page edits.
Can I rearrange individual pages?
Yes. Open Organize pages, select pages across PDFs and use the Move controls, rotation or deletion. Page cards also support desktop dragging. Source labels distinguish identical filenames. Restore document order starts again with all source pages.
Does merging reduce PDF quality?
The tool copies page content instead of rasterizing it or intentionally downsampling it. It does not guarantee that all forms, signatures, bookmarks, annotations or other complex PDF features survive unchanged. Inspect the downloaded copy.
Can I merge password-protected PDFs?
Not here. Remove the password using an authorized PDF application, then add the unlocked copy. A protected file is identified and blocks merging until removed.
Does this change my original PDFs?
No. The result is a new file. Its default filename is merged.pdf; you can enter another name before download. Keep the originals as backups.
Can I merge PDFs on my phone?
Yes. Use the native file picker, Move up/down and optional page controls. Dragging is not required. Modern browser support and available device memory affect unusually complex documents.
Related tools
- PDF Page Organizer
Visually reorder, delete, rotate, duplicate or reverse PDF pages locally and download an organized copy.
- Split PDF & Extract Pages
Extract selected PDF pages, split by ranges or groups, and download separate PDFs privately in your browser.
Missing something?