What is an Independent Variable?

Independent variables are variables in an equation that do not depend on the variation of another variable. The independent variable is usually the input variable while the dependent variable is the output of the equation since the dependent variable depends on the input variable and the equation itself.

If you have two variables, one that you can change freely and another that changes when you change the first, then you'd call the first an "independent variable" and the second a "dependent variable."