Slope-Intercept Calculator
Find the equation of a line in y = mx + b form from two points or a point and slope.
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Request a ToolHow to Use the Slope-Intercept Calculator
Choose a mode, enter your data, and the equation appears instantly in y = mx + b form.
- Select a mode. "From Two Points" calculates the slope automatically. "From Point and Slope" lets you enter the slope directly.
- Enter your data. Provide the coordinates and (if applicable) the slope value.
- Read the equation. The line equation is shown along with the individual slope and y-intercept values.
About Slope-Intercept Form
The slope-intercept form y = mx + b is the most common way to express a linear equation. Here, m is the slope (steepness) and b is the y-intercept (where the line crosses the y-axis). Given any two points, you can find m using (y2-y1)/(x2-x1), then solve for b using b = y1 - m*x1.
This form is widely taught in algebra and used throughout science and engineering because it directly reveals two key properties of a line at a glance.
Frequently Asked Questions
What is slope-intercept form?
Slope-intercept form is y = mx + b, where m is the slope and b is the y-intercept. It is the standard way to write the equation of a straight line.
What if the line is vertical?
A vertical line cannot be expressed in y = mx + b form because the slope is undefined. Vertical lines are written as x = constant instead.
What is the y-intercept?
The y-intercept is the point where the line crosses the y-axis (where x = 0). In y = mx + b, the y-intercept is the value b. It tells you the starting value when x is zero.