A thin client can refer to either a software program or to an actual computer that relies heavily on another computer to do most of its work. A thin client is part of a network, and the client software or computer acts as an interface, while the network server computer does all the real work. In the case of a computer, a thin client is unable to perform many functions on its own. A thin client computer may be a machine designed only for online use, sending and receiving email, and surfing the net. A thin client computer may also be part of a larger network, at a company or school for example.

The thin client computer contains enough information to start up and connect to a more powerful network server, and the server computer provides the rest of the computing horsepower. The thin server may not even have a hard drive. If the thin client computer needs to use a program or save a file, it will connect to the network server computer to do so.

In software terms, a thin client is a program which is mostly interface. The user of the thin client software sees all the data, tools, and features they would on a normal piece of software, but another program running on a remote server does all the work. The reasons someone might use a thin client, both hardware and software versions, include reduced cost, ease of maintenance, ease of use, and security.

A thin client is much more simple than a complete computer. In a situation in which many people need to perform a similar task, it is more cost effective to have one network server computer and many inexpensive thin client computers, than to have many complete computers. Because thin clients are relatively simple, it is much easier to diagnose problems and repair them. A standard computer has a lot of parts, and a thin client only has a few. Fewer parts mean fewer things can go wrong.

People who are not as computer literate will have an easier time using a thin client than a standard computer or software program. With fewer features and functions, a thin client means a person has fewer things that they need to learn about. Thin clients are also relatively easy to secure. A thin client user has restricted access to programs or functions that could breach security. Restricting all the real computing power to a single network server also means that all the security can be focused in one place.

While a thin client is not the right tool for every job, it has many valuable uses. If a user only needs to perform select tasks and does not need all the functionality of a standard computer or program, a thin client may be the right tool for the job.