Enter two points to find the slope of the line and its equation.

Reading the steepness of a line

Slope is how much a line rises or falls for each step it takes sideways, often summed up as rise over run. A positive slope climbs left to right, a negative one descends, a zero slope is flat, and a vertical line has no defined slope because it never moves sideways.

From two points you can find the slope and then the full line equation, which lets you predict any other point on the line. It is the foundation of linear relationships in algebra, physics, economics, and data analysis.

The formula

slope = (y2 - y1) / (x2 - x1)

Worked example

Between (1, 2) and (4, 8), the slope is (8 - 2) / (4 - 1) = 2.

How to read your result

Slope measures steepness: how much y changes for each step in x. A vertical line has undefined slope, and a horizontal line has a slope of zero.

Frequently asked questions

What does slope mean?
The rate of change of y with respect to x, or rise over run.
Why can slope be undefined?
A vertical line has no horizontal change, so the formula divides by zero.
What is the y-intercept?
Where the line crosses the y-axis; the tool gives the full equation.

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