In computer programming, a variable is a facility for storing data. The current value of the variable is the data actually stored in the variable. Depending on the programming language in question, the data stored in the variable can be intentionally altered during the program run. This is why it is called variable. The variable can be referenced by identifiers.

Every variable has a name, called the variable name, and a data type. A variable's data type indicates what sort of value the variable represents, such as whether it is an integer, a floating-point number, or a character.

A variable is the name for a place in the computer's memory where you store some data.

In computer science, a variable is nothing more and nothing less than a named location in memory where information can be stored. In some languages, any kind of information can be stored in a variable while, in others, each variable is given a well defined type by the programmer and only information of the correct type may (or at least should) be stored in that location.

In a program, you may see a line of code such as this one:

area = pi * r * r;

It may look like a math equation, but it is more than a math equation. It is an instruction to the computer to fetch the values from two memory locations, which do have absolute "ID numbers", but for our purposes and the semantics of programming languages are called pi and r, multiply those values together and then store the result in the memory location called area.

In programming languages, a variable can be thought of as a place to store a value in computer memory. More precisely, a variable binds (associates) a name (sometimes called an identifier) with the location; a value in turn is stored as a data object in that location so that the object can be accessed later via the variable, much like refering to someone by name.

The variable holds the value, and it’s placed on the stack so it’s much more efficient.

In many programming languages, including Java, programmers use variables to hold data whose values can change during the execution of a program. A variable is a named memory location that can hold a particular type of data.