The CHM file format and its associated .chm filename extension, is a proprietary file format developed by Microsoft. Its full name is compiled HTML Help. CHM was released to the public in 1997 as a bundle with Microsoft Windows 98 and was primarily designed to facilitate documentation on the Windows platform, particularly help files for software applications that run on the Microsoft Windows platform. Essentially, a CHM file is a collection of HTML files packed as a single compressed file. Though the format is proprietary, it was successfully reverse engineered by the late 90's to early 2000s allowing the development of open source readers that are capable of opening files with the .chm extension. The format was succeeded by the LIT format.
The .7z filename extension is associated with the 7z compressed file archive format and the open source 7-zip compression utility both developed by Igor Pavlov. The format had its initial release in 1999. It consists of a start header 32 bytes in size which contains the signature and link to the ending header, followed by the compressed data, a metadata block, and finally the end header. 7z supports limited recovery options for 7z archive files which can open but for one reason or another cannot extract due to CRC or other data related errors.
FreeFileConvert uses tuned encoding for CHM to T7Z conversions, preserving clarity while trimming file size. Finished audio streams instantly across phones, tablets, desktops, and modern browsers without extra tweaks.
Upload CHM files from desktop, tablet, or cloud storage, queue multiple jobs, and let the converter finish autonomously. Return whenever convenient to download synchronized T7Z results on any device you rely on.
Process up to 5 files sized 1000 MB per batch without splitting queues manually. Mixed-format uploads convert together, producing consistent T7Z audio with dependable progress tracking.
The CHM file format is a binary format that uses the LZX algorithm to compress the HTML data found in the file. The format supports full text searching, indexing, and table of contents, among other useful features.
The 7z compressed archive format was designed to be extensible, to allow it to easily adopt new compression algorithms as they are released. As of writing, the 7z format had support for seven compression algorithms namely LZMA, LZMA2, PPMD, BCJ, BCJ2, BZip2, and DEFLATE. The default algorithm used for compression is LZMA. It is also compatible with the stronger AES-256 encryption algorithm and is capable of compressing file structures of up to 16 Exabyte in size. Filenames can use any characters from the Unicode character set. 7z does not ignore errors found in headers of compressed archives, and as such will not open such archives.
Upload your document file in the CHM format from your device, Dropbox, or Google Drive.
Select T7Z as the output format and click Convert. Adjust optional settings if needed.
Download the converted archive file. Each file stays available for up to 5 downloads.