Slope Calculator

Find the Slope Between Two Points — and Everything Else About That Line

Slope shows up everywhere from algebra homework to reading a grade percentage on a road sign, and the formula itself (rise over run) is simple — it's keeping track of which point is which, and what to do with a vertical line, that trips people up. Plug in two points here and get the slope, the angle the line makes with the x-axis, the distance and midpoint between the points, and the line's equation in all three common forms, plotted on a small graph so you can see it at a glance.

How to use it

• Enter the coordinates of your first point (x₁, y₁) and second point (x₂, y₂).
• The slope, angle, distance, and midpoint update instantly as you type.
• Scroll down to see the line's equation written as slope-intercept (y = mx + b), point-slope, and standard form (Ax + By = C).
• Use "Swap Points" if you entered them in the wrong order — slope comes out the same either way, but it's handy for double-checking.

Real-world use cases

Checking algebra or geometry homework where you need the equation of a line through two given points, figuring out the grade (steepness) of a ramp or road from elevation readings, finding the midpoint between two coordinates for a construction or mapping project, or determining whether two lines are parallel or perpendicular by comparing their slopes.

Frequently asked questions

What does it mean when the slope is "undefined"?

A vertical line (where both points share the same x-coordinate) has an undefined slope, because the rise-over-run formula would require dividing by zero. Vertical lines are written as x = (a constant) instead of the usual y = mx + b form.

How do I find the slope of a perpendicular line?

Take the negative reciprocal of the original slope — flip the fraction and change its sign. If a line has slope 2/3, a line perpendicular to it has slope -3/2. This calculator works that out for you automatically alongside the parallel slope (which is just the same value).

What's the difference between slope-intercept, point-slope, and standard form?

They're the same line written three different ways. Slope-intercept (y = mx + b) is easiest to read the slope and y-intercept from directly. Point-slope (y - y₁ = m(x - x₁)) is the most natural form to write down right after finding a slope and a point. Standard form (Ax + By = C) is often what's expected on tests and is useful for solving systems of equations.

Does the order of the two points matter?

No — the slope comes out identical whether you calculate (y₂-y₁)/(x₂-x₁) or (y₁-y₂)/(x₁-x₂), since both the numerator and denominator flip sign together. The line's equation and graph are also the same regardless of which point you call "first."

What does a negative slope mean?

A negative slope means the line goes downward as you move left to right — y decreases as x increases. A positive slope goes upward left to right, a slope of zero is a flat horizontal line, and an undefined slope is a vertical line.