CAJ to PDF Converter

Convert CNKI CAJ and KDH academic paper files to PDF online. Preserves text and bookmarks. No software installation needed.

Choose a CAJ/KDH file or drop it here

Drop a .caj or .kdh file into the box to get ready

Selected file: -

Note: This tool uploads the file to the server for conversion. Do not upload sensitive files.

About CAJ to PDF

What is CAJ?

CAJ is a proprietary document format used by CNKI (China National Knowledge Infrastructure), primarily for academic theses and dissertations. It can normally only be opened with CAJViewer software.

Supported Formats

CAJ - The most common format, contains an embedded PDF. Conversion extracts and repairs the PDF.
KDH - An encrypted format. Conversion decrypts and repairs the PDF.
HN/C8 - Less common formats with JBIG image compression. Conversion decodes images and assembles a PDF.

Notes

Not all CAJ files can be converted successfully — the format is proprietary and reverse-engineered.
The conversion preserves text content and bookmark outlines where possible.
For files that fail conversion, you can try using CAJViewer's print-to-PDF feature as an alternative.