Storage capacity refers to how much disk space one or more storage devices provides. It measures how much data a computer system may contain. For an example, a computer with a 500GB hard drive has a storage capacity of 500 gigabytes. A network server with four 1TB drives, has a storage capacity of 4 terabytes.
Storage capacity is often used synonymously with "disk space." However, it refers to overall disk space, rather than free disk space. For example, a hard drive with a storage capacity of 500GB may only have 150MB available if the rest of the disk space is already used up. Therefore, when checking your computer to see if it meets a program's system requirements, make sure you have enough free disk space to install the program. If you need more disk space, you can increase your computer's storage capacity by adding another internal or external hard drive.