Convert CHM to PDF — Free Online Converter

CHM (Compiled HTML Help) is Microsoft's legacy help documentation format — a compressed archive of HTML pages, images, and navigation files used as software manuals and technical references since Windows 98. PDF (Portable Document Format) is the universal document standard for sharing, printing, and archiving. Converting CHM to PDF transforms proprietary Windows help files into universally accessible documents that can be viewed, printed, and annotated on every device and platform.

This conversion is the standard approach for making legacy software documentation available outside the Windows Help ecosystem. PDF preserves the visual formatting of the CHM content while adding document features like bookmarks, page numbers, searchable text, and print-ready layout that CHM's browser-like rendering cannot provide.

CHM files are increasingly inaccessible. macOS treats CHM as a potential security risk (quarantine attribute blocks opening), Linux requires third-party viewers, and no mobile platform supports CHM natively. PDF eliminates all platform compatibility issues — every computer, tablet, and phone can display PDF documents without specialized software. For organizations with legacy CHM documentation, PDF conversion is the simplest path to universal access.

PDF also serves documentation workflows that CHM cannot. Printed reference manuals, annotated review copies, formal submissions to regulatory bodies, and archival in document management systems all require PDF. CHM was designed for on-screen help within Windows applications — it was never intended for printing, distribution, or long-term preservation. PDF addresses all of these use cases while maintaining the formatted content of the original help file.