7-Zip is a free and open-source file archiver for compressing and uncompressing files. If you need to save some disk space or make your files more portable, this software can compress your files into an archive with a . 7z extension. WinRAR – faster compression rates while using a lighter algorithm, but is paid software and results in larger files. 7-Zip – slower compression rate and requires more resources but results in smaller files with better compression and is completely free.