Merge PDF: how it works
To merge PDF files, open the Merge PDF tool, add two or more PDFs, drag them into the order you want, and click Merge to download a single combined PDF. Everything happens in your browser — the files are never uploaded — so merging is instant and private.
How to use Merge PDF
- Open the Merge PDF tool and drop in two or more PDF files.
- Drag the files to set the page order of the final document.
- Click “Merge PDFs”.
- Download the combined PDF — it was built entirely on your device.
In your browser vs. uploading to a server
Best for anyone who wants to combine PDFs without uploading confidential documents. Unlike server-based mergers (iLovePDF, Smallpdf), PDFER never transmits your files, so it works offline after the page loads and has no size quota beyond your device's memory.
Frequently asked questions
How do I combine multiple PDFs into one file?
- Add all the PDFs to the Merge tool, drag them into the desired order, and click Merge PDFs. PDFER concatenates them into one document in the browser and downloads it — no upload, no signup.
Can I reorder pages before merging?
- Yes. The files are shown as draggable tiles; reorder them before merging and that order becomes the page sequence of the output PDF.
Are my files uploaded to a server?
- No. PDFER runs entirely in your browser using WebAssembly and JavaScript. Your files are read into memory on your device, processed locally, and never sent to PDFER or any third party. Closing the tab or leaving the tool erases them from memory.
Is it free, and is there a file-size limit?
- Yes, it is free with no account, no watermarks, and no daily caps. Because processing happens on your own device, the only practical size limit is your device's available memory rather than a server upload quota.
PDFER is a privacy-first PDF toolkit built by Kiril Urbonas. Every tool runs entirely in your browser — see our security model and privacy policy.