Our PDF merger combines multiple PDF documents into a single unified file — directly in your browser. The whole operation runs on your device using JavaScript, so the PDFs you drop in never travel to a server, never touch cloud storage, and are discarded from memory the moment you close the tab. That is a meaningful difference if you work with contracts, medical records, tax documents, or anything else you would not want sitting in a third-party upload queue.
Step-by-step guide
- Add your PDFs. Drag files onto the upload area or click to select them from your device. You can add files one at a time or drop a whole folder — there is no fixed limit on how many files you can merge in a single pass.
- Arrange the order. Each file appears as a draggable card. Grab a card by the handle and move it up or down to change where its pages land in the final document. The output follows the exact order shown on screen.
- Remove anything you don't need. Added the wrong file? Click the × on its card to take it out of the set before merging. This does not delete the original file from your computer.
- Merge and download. Click Merge PDFs. The combined document is built in-browser and downloaded automatically. A short file will finish in under a second; a few hundred scanned pages may take a few seconds on a mid-range laptop.
When a PDF merger is the right tool
Merging is surprisingly common in day-to-day document work. Some examples where this tool is the fastest path:
- Combining a cover letter, resume, and portfolio into one submission-ready PDF.
- Bundling a contract with its exhibits and signature page into a single file for archival.
- Assembling a batch of scanned receipts into one document for an expense report.
- Consolidating chapter PDFs into a complete book or course pack.
- Joining split-up tax forms, bank statements, or legal filings before emailing them.
Tips for a cleaner result
- Match page sizes where it matters. PDFs with different page sizes (A4, Letter, legal) merge fine, but if a polished, uniform look matters — for example a portfolio or proposal — consider resizing the outliers first with our Resize PDF tool.
- Add page numbers after merging, not before. If you number pages in each source file separately, the output will have restarting or duplicated numbers. Merge first, then use Add Page Numbers.
- Shrink the output afterwards if you need to email it.A merged PDF with heavy images can get large. Run the result through Compress PDF to bring it under common 25 MB email limits without noticeable quality loss.
- Need to remove or reorder pages, not whole files? Use Reorder PDF or Delete Pages after the merge.
Frequently asked questions
Is there a file size or page limit?
No hard limit is imposed by us. Practical limits come from your device — very large merges (thousands of high-resolution scanned pages) are constrained by available browser memory, so on older devices you may want to merge in two or three passes.
Does merging lose quality?
No. Pages are copied byte-for-byte into the output — text stays selectable, images stay at their original resolution, form fields and bookmarks are preserved wherever possible.
Can I merge password-protected PDFs?
Not directly. Remove the password first with our PDF Password tool (if you know the password), then merge.
Will my files be saved or shared anywhere?
No. All processing happens in your browser using the open-sourcepdf-lib library. Nothing is uploaded, logged, or retained.
Does it work on mobile?
Yes — the merger runs in any modern browser on Android and iOS. Very large merges are slower on phones because of more limited memory, but small- and medium-sized jobs work the same as on desktop.