What is the difference between the Zip, RAR, 7z File Formats?
1. ZIP -- It's a best and easiest format to use if you want to combine multiple files into a single archive file and also want to decrease the size of it. This is the most commonly used file format on the Internet. The interesting thing about this format is that the new operating systems (XP, 7, 8, MAC, Linux) can easily open these files without even installing any kind of software.
2. RAR -- If you want to reduce the file size a lot more, than you should use RAR format. It's the best format to choose when it comes to file size reduction. But in order to compress your files / folders in RAR format, you have to use a software called WINRAR.
3. 7Z -- It's another file compression format, but just like RAR, you have to use a special software name 7-zip to compress your files / folders in this format.
You can use any of these file format according to your file compression need