y Intercept Calculator (2024)

This y-intercept calculator is the perfect tool to calculate the x- and y-intercept of any given line. Additionally, you can use it to find the line equation from its slope and the x- or y-intercept.

Finding intercepts of straight lines is a simple process, but it is pretty common to get the basics mixed up. Let's discuss the following basics in this article so that you're always ready:

  • How do you find the y-intercept of any line?
  • How do you find the x-intercept of any line?
  • How do you find the line equation from its intercepts?

If you're interested in finding the line equation in different forms, we recommend our popular slope intercept form calculator and point slope form calculator.

Slope, intercepts, and the general line equation

We can express the most general form of a straight line in 2-dimensional space as:

ax+by+c=0ax + by + c = 0ax+by+c=0

where:

  • aaa is the coefficient of the xxx term;
  • bbb is the coefficient of the yyy term;
  • ccc is the constant term; and
  • xxx and yyy are the variables representing the two dimensions.

You can plot this line on a graph sheet if you know at least two points that lie on this line. We define the y-intercept of this line as the point at which it crosses (or intersects) the y-axis. Specifically, it refers to the y-coordinate of this point, although it is also common to call the point itself the y-intercept.

Similarly, the line's x-intercept would be the point (or the x-coordinate) where it intersects the x-axis.

The slope (or gradient) of a line is the amount of change in yyy for a change in xxx. You can learn more about the slope of a line using our slope calculator.

We can express the slope, y-intercept and x-intercept of any line ax+by+c=0ax + by + c = 0ax+by+c=0 using these equations:

yc=c/bxc=c/am=a/b\begin{align*}y_c &= - c/b\\x_c &= - c/a \\m &= - a/b\end{align*}ycxcm=c/b=c/a=a/b

where:

  • ycy_cyc is the y-intercept of the line;
  • xcx_cxc is the x-intercept of the line; and
  • mmm is the slope of the line.

In the following sections, we'll prove these equations with an example — but first, let's discuss another form of a line equation.

Slope-intercept form

We can also express a line equation in terms of its slope and y-intercept:

y=mx+cy = mx + cy=mx+c

where:

  • mmm is the line's slope; and
  • ccc is the line's y-intercept, i.e. c=ycc = y_cc=yc.

We could rewrite it to include the y-intercept from the start:

y=mx+ycy = mx + y_cy=mx+yc

You'll find this form very useful when formulating most line equations if you can calculate the slope and y-intercept beforehand.

How do you find the y-intercept of a line?

To find the y-intercept of a line given by ax + by + c = 0, follow these simple steps:

  1. Substitute the value x = 0 into the line equation to get by + c = 0.
  2. Rearrange this equation to find the y-intercept yc, as yc = −c/b.
  3. Verify your results using our y-intercept calculator.

Or, if the line equation is in the slope-intercept form y = mx + c, you can directly extract the term c as the line's y-intercept yc.

For example, consider a line given by the equation 2x+3y2=02x + 3y -2 = 02x+3y2=0. The y-intercept lies on the intersection of the y-axis (the line defined by x=0x=0x=0) and our line 2x+3y2=02x + 3y -2 = 02x+3y2=0. So, we insert x=0x=0x=0 in 2x+3y2=02x + 3y -2 = 02x+3y2=0 to obtain:

20+3y2=03y2=03y=2yc=23\begin{align*}2\cdot 0+ 3y - 2 &= 0\\3y - 2 &=0\\3y &= 2\\\therefore y_c &= \frac{2}{3}\end{align*}20+3y23y23yyc=0=0=2=32

How do you find the x-intercept of a line?

To find the x-intercept of a line given by ax + by + c = 0, follow these simple steps:

  1. Substitute the value x = 0 into the line equation to get ax + c =0.
  2. Rearrange this equation to find the y-intercept xc, as xc = −c/a.
  3. Verify your results using our y-intercept calculator.

These steps are applicable even if the line equation is in slope-intercept form: y = mx + c, giving you xc = −c/m.

Again, consider the line 2x+3y2=02x + 3y -2 = 02x+3y2=0. Its x-intercept lies on the intersection point of the x-axis (y=0y=0y=0) and 2x+3y2=02x + 3y -2 = 02x+3y2=0. So, we insert y=0y=0y=0 in 2x+3y2=02x + 3y -2 = 02x+3y2=0 to obtain:

2x+302=02x2=02x=2xc=1\begin{align*}2x + 3 \cdot 0 - 2 &= 0\\2x - 2 &=0\\2x &= 2\\\therefore x_c &= 1\end{align*}2x+3022x22xxc=0=0=2=1

y Intercept Calculator (1)

How do you find the line equation from its intercepts?

To find the line equation from its x-intercept (xc, 0) and y-intercept (0, yc), follow these steps:

  1. Determine the slope m of the line using m = (0 − yc)/(xc − 0) to get m = −yc/xc.
  2. Formulate the line equation in the slope-intercept form y = mx + c, keeping in mind that c = yc.
  3. Simplify and rearrange as required, or use the equation as it is.

Once again, let's consider the line 2x+3y2=02x + 3y -2 = 02x+3y2=0 with (1,0)(1,0)(1,0) x-intercept and (0,23)(0,\frac{2}{3})(0,32) y-intercept. Can we find the line equation with just these intercepts? Let's find out.

  1. We can determine the slope mmm of this line using these two intercept points (0,23)(0,\frac{2}{3})(0,32) and (1,0)(1,0)(1,0):

m=02310m=23\qquad\begin{align*}m &= \frac{0-\frac{2}{3}}{1-0}\\\therefore m &= -\frac{2}{3}\end{align*}mm=10032=32

  1. Formulate the line equation in the slope-intercept form y=mx+cy = mx + cy=mx+c:

y=23x+23\qquad y = -\frac{2}{3}x + \frac{2}{3}y=32x+32

  1. Simplify this equation and rearrange it to get 2x+3y2=02x + 3y - 2 = 02x+3y2=0.

How to calculate x- and y-intercepts using this y-intercept calculator

You can use this y-intercept calculator in three modes:

  • To calculate the x- and y-intercepts along with the line's slope from its general equation:

    • Choose the mode "Line equation is ax + by + c = 0".
    • Enter the values for a, b, and c, and the calculator will provide you with all the answers!
  • To calculate the slope, y-intercept, and x-intercept of a line from its slope-intercept form:

    • Choose the mode "Line equation is y = mx + c".
    • Enter the values for m and c.
    • Sit back and relax as the calculator takes care of the rest.
  • To find an equation with the intercepts given, use the mode "Line equation is to be determined."

    • Enter the values of x-intercept and y-intercept.
    • Enjoy the fast and accurate results.

Our calculator will also present you with a summary of results and a helpful graph in all these modes!

Pat yourself on your back for learning something new today! We believe you're ready to explain to others how to find the slope, y-intercept, and x-intercept of a line.

FAQ

What is the y-intercept of the line 2x + 3y = -9?

−3 is the y-intercept of the line 2x + 3y = −9. To find this yourself, follow these steps:

  1. Substitute x = 0 into the line's equation to get 2×0 + 3y = −9, or 3y = −9.
  2. Divide both sides by 3 to get y = −3.
  3. Verify your results using our y-intercept calculator.

Do all straight lines have a y-intercept?

No. Some lines run parallel to the y-axis, and thus don't have a y-intercept. However, every line in two dimensions has at least one intercept, be it x- or y-intercept.

y Intercept Calculator (2024)

FAQs

How do I calculate the y-intercept? ›

Since the y-intercept always has a corresponding x-value of 0, replace x with 0 in the equation and solve for y. On a graph, the y-intercept can be found by finding the value of y when x=0. This is the point at which the graph crosses through the y-axis.

How do you write the y-intercept answer? ›

To find y-intercept: set x = 0 and solve for y. The point will be (0, y). To find x-intercept: set y = 0 and solve for x. The point will be (x, 0).

How do you find the y-intercept if there is none? ›

To find the x-intercept, set y = 0 and solve for x. To find the y-intercept, set x = 0 and solve for y. This method of finding x- and y-intercepts will be used throughout our study of algebra because it works for any equation. To graph a line, find the intercepts, if they exist, and draw a straight line through them.

How to find y-intercept with 2 points? ›

Use the slope and one of the points to solve for the y-intercept (b). One of your points can replace the x and y, and the slope you just calculated replaces the m of your equation y = mx + b. Then b is the only variable left. Use the tools you know for solving for a variable to solve for b.

How to find slope and y-intercept? ›

The slope-intercept form of a line is: y=mx+b where m is the slope and b is the y-intercept. The y-intercept is always where the line intersects the y-axis, and will always appear as (0,b) in coordinate form.

How to calculate percentage y-intercept? ›

To find the y-intercept, calculate and , the average of the x- and y-values respectively. Therefore, the complete relationship between glucose concentration and absorbance for the data is y = 0+ 0.002x, or y = 0.002x, where y is the absorbance and x is the glucose concentration.

How to find the value of y? ›

To find a value for y given a value for x, substitute the x-value into the expression. Consider the equation y = 2x + 6. Find the value for y when x = 5: Substitute the value for x into the equation.

What is the y-intercept simplified? ›

Lesson Summary

The y-intercept is what y equals when x is equal to 0, or it can also be stated as where the line of a graph crosses the y-axis. When the equation is in a standard form, then the y-intercept is equal to: General: a x + b y + c = 0 , y intercept is equal to y = − c b.

What is its y-intercept? ›

The y-intercept of a graph is the point where the graph crosses the y-axis. Since the y-intercept is a point on the y-axis, its x-coordinate is always 0. Thus, the coordinates of the y-intercept are of the form (0, y).

What do you write if there is no y-intercept? ›

Answer and Explanation:

The y-intercept of a line is the point where the graph of a line crosses the y-axis. The only lines that do not have a y-intercept are vertical lines of the form x = a, where a ≠ 0. Therefore, graphing a line with no y-intercept is the same as graphing a vertical line, x = a, where a ≠ 0.

What is the y-intercept of the line calculator? ›

The y-intercept of a line is the value of y when x=0. It is the point where the line crosses the y axis.

What is the formula for Y slope-intercept? ›

Slope-intercept form (y=mx+b) of linear equations highlights the slope (m) and the y-intercept (b) of a line.

How to find y-intercept from point-slope form? ›

To find the y-intercept of a line in point-slope form, we use the fact that it occurs where x = 0. That is, we plug x = 0 into the point-slope equation of the line, and then we solve for y. The point-slope form of a line is y - y1 = m(x - x1), where m is the slope of the line, and (x1, y1) is a point on the line.

How to find slope and y-intercept from a graph? ›

The y -intercept b can be found by reading the y -axis where the graph hits the y-axis, and the slope m can be found by finding any two distinct points (x1,y1) and (x2,y2) on the graph, and using the slope formula below.

References

Top Articles
Latest Posts
Article information

Author: Clemencia Bogisich Ret

Last Updated:

Views: 5805

Rating: 5 / 5 (80 voted)

Reviews: 95% of readers found this page helpful

Author information

Name: Clemencia Bogisich Ret

Birthday: 2001-07-17

Address: Suite 794 53887 Geri Spring, West Cristentown, KY 54855

Phone: +5934435460663

Job: Central Hospitality Director

Hobby: Yoga, Electronics, Rafting, Lockpicking, Inline skating, Puzzles, scrapbook

Introduction: My name is Clemencia Bogisich Ret, I am a super, outstanding, graceful, friendly, vast, comfortable, agreeable person who loves writing and wants to share my knowledge and understanding with you.