PDF Merger
Merge multiple PDFs in your browser with drag-and-drop order.
Drop PDFs or click to add
Processed entirely in your browser. Reorder with the arrows before merging.
What is a PDF Merger?
A PDF merger combines multiple PDF files into a single document. Accountants combine receipts, engineers combine design drawings, writers combine draft chapters, HR combines employee paperwork — whenever you have several PDFs that belong together as one document, a merger is the tool. Done well, the output preserves every original page exactly: embedded fonts, hyperlinks, form fields, images, vector graphics.
Our merger runs in your browser. The pdf-lib library parses every input PDF locally, copies the pages into a new document, and saves the merged PDF back to your device. Nothing leaves your browser. That matters for sensitive paperwork — contracts, medical records, tax returns, legal filings — where uploading to a free online PDF service is a privacy risk you probably shouldn't accept.
Page order is drag-to-reorder. Use the up/down arrows on each file to shuffle the order before merging. The merged output places files in the displayed order top-to-bottom. If you need to mix pages from different files (not just files in sequence), use our PDF Splitter to extract specific pages first, then merge those extracts.
What survives the merge. Every visual element in each source PDF. Text and fonts (pdf-lib re-embeds fonts into the merged document). Images at original resolution. Vector drawings and annotations. Hyperlinks. Page dimensions and orientation (portrait and landscape pages mix fine).
What may not survive. Interactive form fields with complex validation sometimes flatten. Digital signatures on the source files typically break in the merged output (the signature covers the original document, not the new combined one). Encrypted PDFs need to be decrypted first — we cannot merge password-protected files.
Practical limits. Browser memory constrains very large merges. 10 medium-sized PDFs (under 5 MB each) merge comfortably on any modern laptop. If you're merging scanned documents with high-resolution page images, expect slower performance and potential memory caps on mobile browsers. For very large jobs, merge in batches.
How to merge PDF files
- Drop PDF files onto the upload zone, or click to pick them.
- Reorder with the up/down arrows so the pages appear in the sequence you want.
- Click Merge — the combined PDF downloads immediately.
- Verify in your PDF viewer that every page landed correctly.
Features
- Combine any number of PDFs in one pass.
- Drag-to-reorder before merging.
- Per-file page count and file size shown inline.
- Preserves fonts, images, hyperlinks, and page orientations.
- 100% local — PDFs never upload.
Frequently asked questions
- Are my PDFs uploaded to your server?
- No. pdf-lib runs entirely in your browser. The source files and the merged output never touch our infrastructure — crucial when merging contracts, medical records, or tax documents.
- Can I merge encrypted/password-protected PDFs?
- Not directly. Remove the password first (some desktop viewers let you do this if you know the password), then merge the unlocked copies.
- Do form fields survive the merge?
- Most basic form fields survive. Complex interactive forms with JavaScript validation or cross-field logic may flatten to static content. If that matters, test a few fields after merging.
- Is there a page limit?
- No hard limit — it's bounded by your browser's memory. 10 medium-sized PDFs merge quickly; 100+ page scanned documents can be slow on mobile browsers. Merge in batches if you hit limits.
- Can I merge different page sizes or orientations?
- Yes. Portrait and landscape pages mix fine. Pages keep their original dimensions in the merged document.
- What happens to digital signatures?
- They break. A digital signature covers a specific document; inserting pages into a new container invalidates it. Sign the merged document after you're done combining.