❓ Frequently Asked Questions – PDF Merger
Is this PDF merger safe? Are my files uploaded?
Your PDF files are never uploaded to any server. This tool works entirely in your browser using PDF.js to parse PDFs and a custom JavaScript PDF writer to merge them. No data leaves your device. This makes it completely safe for confidential documents, legal contracts, medical records and personal files.
How many PDFs can I merge at once?
There is no hard limit on the number of PDFs you can add. However, since all processing happens in your browser, very large files or many files may slow down the process. For best performance, keep the total combined size under 100MB. Each individual file can be up to 50MB.
Can I choose specific pages from each PDF?
Yes! Each PDF file in the list has a page range input. You can type a range like "1-5" to include only pages 1 through 5, or "1,3,7" to include specific pages, or "1-3,8,10-15" to combine ranges. Leave the field empty to include all pages from that PDF. Invalid page numbers are automatically ignored.
Can I reorder the PDF files before merging?
Yes. Drag and drop the PDF file cards to reorder them. The merged PDF will follow the exact order shown in the list. You can also use the up/down arrow buttons on each card if drag-and-drop is not convenient on your device.
Why does the merged PDF look slightly different from the original?
This tool re-renders each PDF page to a canvas and re-encodes it as JPEG images in the merged PDF. This approach works universally across all PDF types (text-based, scanned, mixed). However, it means the output is image-based rather than text-based, so text in the merged PDF is not selectable. For text-selectable merging, use a server-based tool like Adobe Acrobat or Smallpdf.