A horizontal asymptote is a horizontal line that tells us how a line will behave at the edge of a graph.

It indicates the general behavior on a graph usually far off to its sides.

**Formula to calculate horizontal asymptote.**

- If the degree of the denominator (D(x)) is bigger than the degree of the numerator (N(x)), the HA is the x axis (y=0).
- If the degree or the numerator is equal to the degree of the denominator, the HA will be N(x) / D(x).
- If the degree of the numerator is bigger than the degree of the denominator then the HA is none.

**Example**:

Suppose the degree of the numerator is x^2 while the degree or the denominator is x.

Since the N(x) is bigger than the D(x), the HA will be none.