The complex plane, like the coordinate plane, is a two-dimensional coordinate system that has two axes — the real axis and the imaginary axis, which are perpendicular to each other and intersect at the origin. The complex plane allows complex numbers to be represented graphically.

A complex number $z=a+bi$ corresponds to the point $(a,b)$ in the complex plane. From this, every real number lies on the horizontal axis and every pure imaginary number lies on the vertical axis.