Hardware or software that is scaleable can be easily expanded to suit future requirements. For instance, a particular application program may be set up to run for two concurrent users but can be scaled up for more users if the company using it needs to expand in the future. This is very important quality when you are making purchasing decisions.

In a scaleable system, growth is possible, if demand grows. Notebooks, for example, are not very scaleable, because it's hard to add additional hardware. Rack mounted servers, on the other hand, are scaleable, with the ability (in some very high-end servers) to add extra hard drives and RAM while the system is running.

A piece of software or computer operating system that can be transferred to a bigger and faster computer with more processors without any need for a program or settings change. See also Software, Operating System and Processor.