YIntercept (Mathematics Glossary)
What Is the YIntercept?
The yintercept of a line is the ycoordinate of the point where a line, curve or surface crosses the yaxis.
What Is the YIntercept of a Line?
The yintercept of a line is the ycoordinate of the point where the line crosses the yaxis.
The line below crosses the yaxis at y = 3. The yintercept of the line is 3.
Read more about finding the yintercept of a line
The YAxis Crosses the XAxis When X = 0
The yaxis crosses the xaxis when x = 0.
This means that all points on the yaxis have x = 0.
This is useful, because it let's us find the yintercept of a line or a curve when we know its equation.

Finding the YIntercept of a Line from a Linear Equation
The yintercept of a line can be found from the equation of a line (called a linear equation).
The slopeintercept form of a linear equation is:
In this equation, y and x are variables. m and c are letters that stand in for numbers. An example of a linear equation would be y = 2x + 1 (the m = 2 and c = 1).
The yintercept occurs when the line crosses the yaxis. On the yaxis, x = 0.
The yintercept of this equation is c.

Finding the YIntercept of a Line from a Function
The linear equation is an example of a function. For any value of x, it tells you y.
We can find the yintercept of any function by substituting x = 0.
More About the YIntercept
The slider below gives more information about the yintercept:
Interactive Test
showHere's a second test on the yintercept.
Here's a third test on the yintercept.