Drop PDF files here
or click to browse
// drag, reorder, merge — your pdfs stay in your browser
Merge multiple PDF files into one document instantly in your browser. No upload, no sign-up, 100% free and private. Drag, reorder, and combine PDFs in seconds.
Drop PDF files here
or click to browse
Drop files onto the drop zone or click Browse to select multiple PDFs from your device.
Drag and drop the file cards to set the exact order they'll appear in the merged output.
Click Merge PDFs — the combined file is built in your browser and downloaded instantly.
PDF Merger combines multiple PDF documents into a single file, entirely inside your web browser using the PDF-lib JavaScript library. Your files are never sent to any server — all processing happens locally on your device, ensuring complete privacy.
* Performance depends on your device RAM and PDF complexity. Very large files may take a few seconds.
No. PDF Merger runs entirely in your browser using JavaScript. Your files are never sent to any server, making this tool completely private. Once you close the tab, nothing is retained.
There is no hard limit on the number of files. You can merge as many PDFs as you like, though performance depends on your device's available RAM and the total size of the files.
Currently, password-protected or encrypted PDFs are not supported. You will need to remove the password protection first using a PDF reader before merging.
Yes. The merger uses PDF-lib, which preserves all embedded fonts, images, vector graphics, and page formatting from the original files.
Absolutely. After adding your files, you can drag and drop them in the file list to set the exact order. The pages will appear in the merged PDF in the order shown.
There is no server-imposed limit because processing happens locally. However, very large PDFs (hundreds of MB) may slow down or exceed your browser's memory. For best results, keep total input size under 500MB.
PDF Merger works in all modern browsers including Chrome, Firefox, Safari, and Edge. Internet Explorer is not supported as it lacks the modern JavaScript APIs required.
The merged file is named merged.pdf by default. You can rename it after downloading using your operating system's file manager.
A PDF merger is a tool that combines two or more separate PDF documents into a single, unified file. Instead of sending multiple attachments or flipping between different documents, a merged PDF gives you one clean file that's easy to share, archive, and review. PDF Merger by JLV DevTools does this entirely in your browser — no account required, no files uploaded, nothing stored.
There are dozens of everyday situations where merging PDFs saves time and frustration. Here are some of the most common:
Traditional online PDF tools require you to upload your files to a remote server, where they are processed and then sent back to you as a download link. This approach has real privacy implications — your files pass through systems you don't control, and many services retain them for days or even weeks.
JLV PDF Merger takes a different approach. It uses PDF-lib, a powerful open-source JavaScript library that reads and writes PDF files entirely within your browser's memory. When you add files, they are loaded into the browser's ArrayBuffer system. When you click Merge, PDF-lib copies each page from each source document into a new PDF document object, then converts the result to bytes and triggers a download — all without a single byte leaving your device.
The result is a tool that is not only private but also extremely fast, since there is no network round-trip involved.
Using PDF Merger is straightforward:
merged.pdf. Rename it as needed.PDF (Portable Document Format) is a file format developed by Adobe in 1993. It was designed to present documents consistently across different operating systems, software, and hardware. A PDF file contains a hierarchy of objects: pages, fonts, images, annotations, and metadata, all stored in a compact binary format with a cross-reference table that allows random access to any object.
When merging PDFs, the tool must copy all referenced objects from each source file into the target document while resolving any object ID conflicts. PDF-lib handles this automatically, including embedded fonts and images, so the merged document looks identical to the originals.
PDF Merger is designed with privacy as the default. Because all processing happens in your browser:
This makes PDF Merger safe for sensitive documents including medical records, legal contracts, financial statements, and personal identification documents.
PDF-lib is an open-source JavaScript library maintained by Andrew Dillon. It supports creating PDFs from scratch as well as modifying existing PDFs — including merging, splitting, rotating pages, adding text and images, filling form fields, and embedding fonts. PDF Merger uses the CDN-hosted version of PDF-lib so no installation is required.