PDF Merger is a free, browser-based tool that combines multiple PDF files into a single document without uploading anything to a server. Users drag and drop their PDF files into the interface, arrange them in the desired order using a simple drag-to-reorder list, and download the merged result in seconds. The tool is built on pdf-lib, a JavaScript library that handles all PDF manipulation entirely within the browser. This means sensitive documents, such as contracts, financial reports, legal filings, and medical records, never leave the device. PDF Merger is used daily by office workers assembling multi-part reports, students combining lecture notes and appendices, freelancers packaging deliverables for clients, and HR professionals compiling application packets. It handles standard PDFs of any page count and size, limited only by the available memory in the browser. No account, no installation, and no file size limit imposed by a server. The merged PDF preserves the original page content, fonts, and embedded images from each source file.
When assembling multi-document packages, the order of files matters as much as the files themselves. PDF Merger's drag-to-reorder interface lets users arrange source PDFs precisely before merging, which is particularly useful when combining a cover letter, CV, portfolio samples, and reference list into a single job application PDF, or when attaching financial statements in chronological order to a board report. The tool processes all files client-side using pdf-lib, so there are no round trips to a server and no waiting for uploads or processing queues. Because no data leaves the device, the tool is appropriate for use with confidential documents in legal, medical, financial, and HR contexts where sending files to third-party servers would create compliance or privacy concerns. The merged output is a standard PDF compatible with all PDF viewers including Adobe Acrobat, Preview, and browser-based viewers. For users who need to merge only specific pages from each source file rather than entire documents, combining PDF Merger with PDF Splitter gives full control: split each source to isolate the needed pages, then merge the resulting files. The tool works on Windows, macOS, Linux, iOS, and Android through any modern browser with no installation required.