Independent Variable

Pronunciation: /ˌɪn dɪˈpɛn dənt ˈvɛər i ə bəl/ ?

Graph of f(x)=x^2
Figure 1: Graph of f(x)=x2

An independent variable is a variable whose value can vary independently of other variables. Another way to state this is the value of the independent variable does not depend on the value of any other variable. In functions, an independent variable is also called an input variable.

In figure 1, f(x)=x2, the independent variable is x. You can tell the input variable when using function notation because it is inside the parenthesis of the function declaration.

Cricket Population
Figure 2: Table of cricket population by year.

The table in Figure 2 represents a function. The independent variable is Year. This is because the year exists independently of the cricket population, and the cricket population is dependent on the year.


  1. independent variable. Encyclopedia Britannica. (Accessed: 2010-02-11). variable.
  2. Long, Edith and Breknke, W. C.. Algebra, first course, pg 208. The Century Co., 1913. (Accessed: 2010-01-22).
  3. Bettinger, Alvin K. and Englund, John A.. Algebra and Trigonometry, pp 53-54. International Textbook Company, January 1963. (Accessed: 2010-01-12).

Cite this article as:

Independent Variable. 2010-02-11. All Math Words Encyclopedia. Life is a Story Problem LLC.


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Revision History

2010-02-11: Added "References" (McAdams, David.)
2008-08-09: Added vocabulary link 'vary', clarified sentence on independent variable and function notation (McAdams, David.)
2007-07-12: Initial version (McAdams, David.)

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