Learn about .rar files. .Rar files are popular with Windows users (the main .rar expander being WinRar), but you can also open .rar files on your Mac.
Use StuffIt Expander if your computer runs Mac OS X. This program is built in to the system. You can use StuffIt Expander to decompress .rar files on your Mac (see Resources below). StuffIt Expander also opens several other compressed file types.
Use a decompression tool such as UnrarX to open .rar files on a Mac (see Resources below). UnrarX is available for Mac OS X 10.0 and higher.
Download software such as RAR Expander, which supports Apple scripts and can also expand multiple archives at once (See Resources below).
Open .rar files on your Mac by dragging the files and then dropping them onto the icon for your expander software. The software will then decompress and open the files so you can use them.