Positive slope
Between (2, 3) and (6, 11), m = (11 − 3) / (6 − 2) = 8/4 = 2.
Find slope from two points
Slope calculator
Enter two coordinate points to calculate rise, run, and slope, including horizontal and vertical-line cases.
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Formula and steps included
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Formula
The slope formula
Slope: m = (y₂ − y₁) / (x₂ − x₁), when x₂ ≠ x₁
Slope measures vertical change per unit of horizontal change. It is often described as rise over run and keeps the subtraction order consistent for both coordinates.
A positive slope rises from left to right, a negative slope falls, and zero is horizontal. When the run is zero, the line is vertical and its slope is undefined.
How to use the formula
Label the two points
Assign the coordinates consistently as (x₁, y₁) and (x₂, y₂).
Calculate the rise
Subtract y₁ from y₂ to find the vertical change.
Calculate the run
Subtract x₁ from x₂ in the same point order used for the y-values.
Divide and interpret
Divide rise by run when the run is nonzero, then use the sign to describe the line's direction.
Worked examples
Slope calculator examples
Vertical line
Between (4, −1) and (4, 7), the run is 4 − 4 = 0, so the slope is undefined.
Common questions
Slope calculator FAQ
What is the slope of a horizontal line?
Its slope is zero because the y-values do not change, making the rise zero while the run is nonzero.
Why is a vertical line's slope undefined?
Both points have the same x-value, so the run is zero. The slope formula would require division by zero, which is undefined.
Does switching the two points change the slope?
No, if you reverse both subtraction orders. Both the rise and run change sign, leaving their quotient unchanged.
Are my coordinates stored?
Your coordinates are not saved by default or uploaded. You can opt into Remember on this device or download a local JSON backup.