PDF Merger
Merge PDFs locally with full order control.
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PDF Merger combines multiple PDF files into one document entirely in your browser. Reorder files, merge locally with a Web Worker, and download the result—no uploads and no account required.
How it works
Add two or more local PDFs, rearrange them with Move up/down, then Merge. ToolHub validates size and page limits, runs pdf-lib in a worker when available, and returns a single downloadable PDF Blob.
Benefits
- 100% client-side merge with no server upload
- Explicit order controls before combining
- Hard file, total-size, and page guards
- Clear errors for encrypted source PDFs
Use cases
- Combine a cover letter with a resume PDF
- Assemble report chapters into one handout
- Stack invoices or receipts for accounting
- Build a single packet from scanned pages
Best practices
- Confirm order with Move up/down before merging
- Stay under 50 MB per file and 100 MB total
- Unlock password-protected PDFs first
- Keep originals until you verify the download
Common mistakes
- Expecting encrypted PDFs to merge silently
- Adding only one file and wondering why Merge is disabled
- Ignoring the 500-page combined limit on huge packs
- Assuming form fields always remain fillable after merge
Privacy
PDFs are processed locally with pdf-lib and optional Web Workers. ToolHub never receives your files. Clear downloads from shared devices when finished.
Frequently asked questions
- Does PDF Merger upload my documents?
- No. Files are read in your browser and merged with pdf-lib inside a Web Worker when available. Nothing is sent to a ToolHub server.
- How do I control merge order?
- After adding PDFs, use Move up and Move down on each row to set the final page order. The list top becomes the start of the merged file.
- What are the file size limits?
- Each PDF can be up to 50 MB, with at most 20 files and 100 MB combined. Merged output cannot exceed 500 pages. Limits appear under the file picker.
- Can I merge password-protected PDFs?
- No. Encrypted PDFs fail with a clear error. Remove the password in another app, then merge the unlocked copies locally.
- Will merge work on a phone?
- Yes for modest files. Large merges can be slow or time out on low-memory devices—close other tabs and prefer Wi‑Fi when combining big documents.
- Does the original formatting stay intact?
- Pages are copied as-is from each source PDF. Fonts, images, and layout on those pages are preserved; interactive forms and some advanced features may not carry over.