Slope Calculator
Enter two points below to instantly find the slope of the line through them.
The Slope Formula
m = (y₂ − y₁) / (x₂ − x₁)
Worked example
Points (2, 3) and (6, 11).
m = (11 − 3) / (6 − 2) = 8 / 4 = 2
Slope = 2, so the line is y = 2x − 1
A second example
Points (−2, 5) and (3, −5).
m = (−5 − 5) / (3 − (−2)) = −10 / 5
Slope = −2, a line falling steeply left to right
Keep going
- Slope is the first piece of a line's slope-intercept equation; the slope-intercept calculator takes that number and builds the full y = mx + b form. Slope-Intercept Form Calculator
- Once you have a slope, point-slope form builds a line's equation from it and a single point; the point-slope calculator does that construction directly. Point-Slope Form Calculator
Frequently Asked Questions
What is the slope formula?
Slope (m) equals rise over run: m = (y₂ − y₁) / (x₂ − x₁), using any two points on the line.
What does a negative slope mean?
A negative slope means the line falls as it moves left to right. A positive slope rises, a slope of zero is flat, and a vertical line has an undefined slope.
Can you find slope from just one point?
No — slope describes the rate of change between two points, so you need at least two points (or one point plus the slope itself) to define a line.
How does slope relate to parallel and perpendicular lines?
Parallel lines always have the exact same slope. Perpendicular lines have slopes that are negative reciprocals of each other — if one line has slope 2, a line perpendicular to it has slope −1/2, since 2 × (−1/2) = −1.
What's a common mistake when calculating slope?
Subtracting the coordinates in a mismatched order, like (y₂ − y₁) over (x₁ − x₂). Both the numerator and denominator need to treat the same point as "first" and the same point as "second," or the sign of the slope comes out flipped.
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