I have a .rar file, (already compressed) and I need to split it. Can this be done through the WinRAR UI?
Yes, you can do it using WinRAR.
Open WinRAR window and navigate to the folder which your file is located in that WinRAR window.
Right click on your RAR file and select "Add files to archive" (alternatively you can press Alt+A).
In the opened window, give a new name to your to-be-split file (e.g. Archive_2.rar). Then, under "Compression Method", select "Store". Input your desired value inside "Split to volumes, bytes" box, click OK and you're done.
Open WinRAR Select Tools --> Wizard Select Create New Archive Select Original filename.rar file Enter the destination folder and new archive file name Enter the required size (500mb, 700mb,2 gb, 4.4 gb) Click Finish button.
Automatically create all archive files in selected folder.
In my case, I had a big 260GB RAR file (backup from a server) and I wanted to split the archive into smaller 2GB units.
I went to the Tools menu and ran the Archive Conversion utility.
Open the Big archive file you want to convert into Multi-volumes, and Press ALT + Q or select 'Convert Archive' from the Tools Menu.
Then Click on 'Compression' button towards the middle of the screen on the Right side, and chose the desired size for the Multi-Volume archives.
Hope this helps!