Parallel and Perpendicular Line Calculator

Find parallel and perpendicular lines step by step

The calculator will find the equation of the parallel/perpendicular line to the given line passing through the given point, with steps shown.

For drawing lines, use the graphing calculator.

Find the equation of the line to the line passing through the point (, )

Enter the equation of a line in any form: y=2x+5, x-3y+7=0, etc.
If you need to find a line given two points or a slope and one point, use line calculator.
To find a slope, use slope calculator.

If the calculator did not compute something or you have identified an error, or you have a suggestion/feedback, please write it in the comments below.

Introducing the Parallel and Perpendicular Line Calculator, an online tool for quickly finding parallel and perpendicular lines. This calculator will help you determine their slopes and equations, as well as understand the underlying process.

How to Use the Parallel and Perpendicular Line Calculator?

  • Input

    Begin by entering the equation of the line you have. Provide the coordinates of the specific point through which the new line (parallel or perpendicular) should pass. Select your desired line orientation: whether you want a line that's parallel or one that's perpendicular to the given line.

  • Calculation

    Once you've input all the necessary information, click the "Calculate" button.

  • Result

    The calculator will instantly display the required parallel or perpendicular line equation based on your inputs.

What Are Perpendicular and Parallel Lines?

  • Perpendicular Lines

    Perpendicular lines are straight lines that form a right angle (90 degrees). In the context of the coordinate plane, if two lines with the slopes $$$m_1$$$ and $$$m_2$$$ are perpendicular, then their slopes are negative reciprocals of each other. Mathematically, it can be written as follows:


    This means that the slope of a line perpendicular to another is the negative reciprocal of the original line's slope.

    For example, suppose we have a line $$$\mathit{L_1}$$$ whose equation is $$$y=2x+1$$$. Its slope $$$m_1$$$ is $$$2$$$.

    To find the slope $$$m_2$$$ of a line $$$\mathit{L_2}$$$ perpendicular to $$$\mathit{L_1}$$$, we use the formula for slopes:$$2m_2=-1$$$$m_2=-\frac{1}{2}$$

    Thus, the line $$$\mathit{L_2}$$$ with the slope $$$-\frac{1}{2}$$$ is perpendicular to $$$\mathit{L_1}$$$.

  • Parallel Lines

    Parallel lines are straight lines that run in the same direction and are always the same distance apart, ensuring they never meet, no matter how long they are extended. In terms of slopes, two lines are parallel if they have the same slope but different y-intercepts.

    The formula for slopes in this case is the following:


    where $$$m_1$$$ and $$$m_2$$$ are the slopes of the two parallel lines.

    For example, let's consider let's consider a line $$$\mathit{M_1}$$$ with the equation $$$y=3x-2$$$. Its slope is $$$3$$$.

    For a line $$$\mathit{M_2}$$$ to be parallel to $$$\mathit{M_1}$$$ it must have the slope equal to $$$3$$$. Thus, any line of the form $$$y=3x+c$$$ (where $$$c$$$ is any constant other than $$$-2$$$) will be parallel to $$$\mathit{M_1}$$$. An example of such line is $$$y=3x+5$$$.

In What Areas Are Perpendicular and Parallel Lines Used and Why Are They Important?

The importance of both perpendicular and parallel lines in various areas is evident:

  • Urban Development: The layout of city grids often includes perpendicular avenues that form distinct block patterns.
  • Architecture: The foundation and aesthetics of buildings are heavily based on the principles of parallelism and perpendicularity.
  • Design: Whether it is graphic or product design, perpendicularity and parallelism play an important role in enhancing functionality and visual appeal.

Why Choose Our Parallel and Perpendicular Line Calculator?

  • Unparalleled Accuracy

    Using advanced computational techniques, our calculator guarantees the accuracy of every calculation.

  • Intuitive Design

    Our platform boasts a clean, straightforward design, enabling users to obtain results without unnecessary complications.

  • Multifunctionality

    In addition to finding parallel lines, the calculator can also find perpendicular lines.

  • Learning Enhanced

    Beyond computing, we prioritize understanding. Our tool explains the results, deepening your knowledge of the concepts of parallel and perpendicular lines.


Do two perpendicular lines always intersect?

Yes, two perpendicular lines always intersect; when they do, they form a right angle (90 degrees).

What are perpendicular lines?

Perpendicular lines are two lines that intersect at a right angle. Regarding their slopes, if one line has the slope $$$m$$$, the perpendicular line's slope will be the negative reciprocal, which is $$$-\frac{1}{m}$$$.

Are the results provided by the calculator accurate?

Our calculator is built using advanced algorithms to ensure speed and accuracy.

What are parallel lines?

Parallel lines are two or more straight lines that run in the same direction and remain equidistant from each other throughout their entire length. This means they never intersect or touch, regardless of how far they are extended. Regarding their slopes on a coordinate plane, parallel lines have identical slopes. For instance, if one line has the slope that equals $$$m$$$, any other parallel line will also have the slope that equals $$$m$$$.