Why merge PDFs locally instead of uploading them
Most online PDF mergers work by uploading your files to a server, combining them there, and sending the result back. That means a copy of every document you merge — contracts, invoices, tax forms, medical paperwork — passes through infrastructure you don't control, however briefly.
This tool doesn't do that. The merge runs in a Web Worker inside your browser tab, using the same page-copying approach any PDF library uses, just without the network round trip. Open your browser's network tab, merge a few files, and watch — nothing is sent.
How it works
- Drop two or more PDF files, or click to browse.
- Reorder them with the up/down arrows — the merged file follows this order exactly.
- If a file has bookmarks, form fields, or a digital signature, you'll see exactly what will be lost before you commit.
- Click Merge — the combined PDF downloads straight to your device.
What merging preserves, and what it doesn't
Page content — text, images, vector graphics — carries over exactly. What doesn't survive a merge, in any PDF tool, not just this one: document-level bookmarks/outlines, fillable AcroForm fields, and digital signatures (any re-save invalidates a cryptographic signature). This tool tells you before you merge if a file has any of these, rather than silently dropping them.
Frequently asked questions
Does this upload my PDFs anywhere?
No. Every file is read and combined directly in your browser using the File API and a Web Worker — there is no upload and no server round trip. That matters for contracts, financial statements, medical records, or anything else you'd rather not hand to a third-party server.
What happens to bookmarks and form fields in the merged file?
They're lost. Rebuilding a PDF from multiple sources means each page is copied into a new document, which does not carry over the original outline (bookmarks) or AcroForm fields — this is a limitation of how PDF page-copying works, not something specific to this tool. If any of your files have bookmarks or fillable fields, you'll see a warning naming exactly what will be lost before you merge.
Can it merge password-protected PDFs?
Yes — if you have the password. You'll be prompted to enter it for that specific file; it's used locally to unlock the document and is never sent anywhere.
Is there a limit on file count or size?
No hard limit, but very large combined inputs (a couple hundred MB or more) will take noticeably longer and use more of your browser tab's memory, since everything happens on your device rather than a server.
Does merging compress or shrink the file?
No. Merging concatenates pages as-is; it doesn't re-encode images or fonts, so the output size is roughly the sum of the inputs. Compression isn't something this tool attempts — it would require re-encoding embedded images in a way that can degrade quality unpredictably.
Can I remove the merged file's metadata (author, title, etc.)?
Not here — use the Shredder's PDF metadata remover on the merged output for that. This tool focuses on combining pages.
Related tools
- Split PDF — pull a page range out of a PDF into its own file.
- Rotate PDF — fix sideways or upside-down pages before merging.
- Delete PDF Pages — remove blank or unwanted pages before combining files.
- Extract PDF Pages — pull specific pages out to include in a merge.
- Fill PDF Form — fill in a fillable form before merging it with a cover letter or attachments.
- Sign PDF — add a drawn or typed signature before merging.
- Shredder — Remove PDF Metadata — strip author, title, and other metadata from the merged file.
- Remove PDF Line Breaks — clean up text copied out of a PDF.
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