What slope means
Slope measures how steep a line is: how much y changes for each step in x. It's the rise over the run — the change in y divided by the change in x between two points. A positive slope rises left to right, a negative one falls, a slope of zero is flat, and a vertical line has an undefined slope because x doesn't change.
From two points to a full line
Once you have the slope m, the line's equation follows as y = mx + b, where b is the y-intercept — the value of y when x is zero. This tool computes both, plus the angle the line makes with the horizontal and the straight-line distance between your two points, and draws the line so you can see it.
Where slope shows up
Beyond algebra homework, slope is the gradient of a road or ramp, the rate of change in a trend line, the pitch of a roof, and the speed on a distance-time graph. Any time one quantity changes steadily with another, slope is the number that describes how fast.
Frequently asked questions
What if the two x-values are the same?
Then the line is vertical and the slope is undefined, because you'd divide by zero. The tool shows this instead of a number.
How do I get the angle from the slope?
The angle is the arctangent of the slope. The tool does this for you and shows it in degrees alongside the equation.