Merge PDF
Combine several PDF files into one document in the order you choose. Merge as many files as you like and download the result - everything runs locally in
Drop your PDF file here
or click to browse files
Combine several PDF files into one document in exactly the order you choose. Add the files, arrange them, and download a single PDF that contains every page from every source document. Scanned pages, forms and exported reports can all be mixed - the pages are copied over without being re-rendered, so text stays selectable and quality is unchanged.
Typical uses: joining a signed cover sheet with an appendix, collecting several invoices into one file for accounting, or assembling a scanned contract from separate photos. Everything happens locally with pdf-lib, so confidential documents are never sent to a server.
How to merge PDF files
Add two or more PDF files
Drag them into the order you want
Download the merged PDF
FAQ
How many files can I merge?
There is no fixed limit - it depends on your device memory. Dozens of ordinary documents merge without trouble; a merge of hundreds of large scans may be slower on mobile.
Are bookmarks and form fields preserved?
Pages, text and images are copied exactly. Interactive form fields are preserved as part of the page content, but a field that appears in several source documents may not behave as a single combined form.
Does merging reduce PDF quality?
No. Pages are copied from the source documents rather than re-rendered or re-compressed, so images and text keep their original quality.
Can I change the page order afterwards?
Yes, reorder the file list before merging, or merge first and then use the Organise PDF tool to rearrange, rotate or delete individual pages.
Are my PDFs uploaded?
No. The merge runs in your browser; the files never leave your device.
Can I merge password-protected PDFs?
Only documents that open without a password can be read. If a file is encrypted, remove the protection first and then merge.
At a glance
| Input | |
|---|---|
| Multiple files | Yes |
| Where it runs | In your browser - files are never uploaded |
| Works offline | Yes — once the page has loaded |
| Price | Free, no sign-up, no watermark |
PDF versions, standards and compatibility
PDF 1.4 is readable by essentially everything and is the safe default for forms and general sharing. PDF 1.7 added better compression and is what most modern software writes. PDF/A is an archival variant that embeds every font and forbids outside dependencies so the file will still render identically in twenty years - archive offices and some government submissions require it, and it is a poor choice for everyday files because it is larger. Encrypted PDFs need the protection removed before any other tool can touch them, and a permissions (owner) password is weaker than an open password: it is meant to discourage printing and copying, not to keep anyone out.
What actually makes a PDF large
Almost all of a bulky PDF is images, not text. A ten-page scan can be 40 MB while a 300-page text document is often under 2 MB. That is why compression targets embedded pictures: it downsamples them to a sensible resolution (150 dpi is usually enough for on-screen reading, 300 dpi only if someone will print it) and re-encodes them more efficiently. Text, bookmarks, links and form fields cost almost nothing and should never need to be removed. If a file stays large after compression, it usually contains either a lot of high-resolution images that the compression setting did not touch, or embedded fonts and attachments you can strip.