PDF Merger

About this tool

Merge multiple PDF files and export the result. You can reorder them on screen, and all processing happens entirely in your browser (no data is sent).

Upload PDF files and merge them

Input & settings

Select PDF files (multiple)

Output file name

Preview & reorder

Drag and drop to change the order. Thumbnails show the first page.

How to use

Select or drag-and-drop one or more PDF files.
Reorder thumbnails via drag and drop; use the × button to remove a file.
Enter the output file name (default: merged.pdf).
Click “Merge” to combine the files and “Download” to save the result.

Notes

PDFs with different page sizes merge without resizing; each page retains its original dimensions.
Large files (100 MB or more in total) may take longer to process.
Extremely large page counts can hit browser memory limits and cause errors.
Encrypted PDFs are not supported.

Libraries used:

pdf-lib.min.js (MIT License)
pdf.js & pdf.worker.js (Apache License 2.0)
Sortable.js (MIT License)