How to split a big folder or file into small folders or files and compress into size controlled files automatically?
Uploading files to the Web is a common practice to share, store, and transfer files over internet. Uploading large files and folders requires time and patience. For example, if you have a 300M folder with hundreds of files beneath want to upload from local computer to remote server through FTP client, such as CuteFTP, FileZilla, it is time consuming to upload them to FTP server. If you want to send this big folder, you can not directly send folders as attachment. In such circumstances, you need to compress big files or folders into smaller file(s) before uploading or attaching to emails. If the output zipped file is still too large to be uploaded or send via email in one time, you can split a large file or folder into several small files using WinRAR automatically. Best of all, this file compressor can equally split your folder into small files in limited size, say 5M, 8M or any other file size limit preset. This feature is extremely useful. When you have a lot of sub files/folders, it is tedious to find out and group sub files/folders into groups which is in certain file size when zipped. WinRar is the best application to not only automatically split big folders and files in to several chunks but also to compress them while splitting. Best of all, it will retain your file directory and structure, you can decompress or unzip the compressed files without affecting their original file structure.
How to Compress a big file or folder into small size limited files?
1. Right click on the folder or file you like to split and compress, choose the option “Add to archive” from the jump gown menu. You can even split large single files such as movies, videos, PDF documents. This feature makes huge video sharing over the internet much easier.

2. Under the option Split to volumes, bytes. You can choose from existing profiles or manually enter the desired maximum size of each output file chunk. There are preset profiles you can choose to quickly apply.
By default, it accepts bytes in numbers, such as 1048576 for 1M, you can use this free online tool to convert bytes to Kilobytes, Megabytes, Gigabytes and Vice Versa. http://whatsabyte.com/P1/byteconverter.htm
3. Click Ok, WinRar will compress the source folder or file and splits it in to several small compressed files in preset file size.
There could be a problem though when you upload the output compressed files in RAR format to a web hosting control panel which does not support RAR file decompression. Most web hosts seems to support zip files not RAR files. The WinRAR however can not help you split large folders and compress them into zip files automatically. A workaround to this issue is to split the large folder into several RAR files in a batch, then decompress these RAR files one after another, after that go to compress them into zip files one by one.