Slope Calculator
The slope, percent grade and angle of a line through two points.
Result
Slope (m)
0.750
Grade (%)
75.0
Angle (°)
36.87
How it works
Slope measures steepness: the change in y divided by the change in x, m = (y₂ − y₁) ÷ (x₂ − x₁). It is the "rise over run" — how much you climb for every unit you move sideways. This calculator also returns two other readings of the same quantity. Percent grade is the slope times 100, the form used on road signs: a 10% hill rises 10 metres over 100 horizontal metres. The angle is arctan(slope), which is what surveyors and roofers work in. The sign carries the direction: positive slopes rise from left to right, negative ones fall. A slope of zero is a horizontal line, and a vertical line has no defined slope at all, because the change in x is zero and dividing by zero is undefined — that is why vertical lines break the formula rather than giving an infinite answer.
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Frequently asked questions
What is percent grade?
The slope times 100 — a 10% grade rises 10 units for every 100 travelled horizontally.
What if the line is vertical?
A vertical line has an undefined slope; here it is shown as a 90° angle.
What does a negative slope mean?
The line descends as you move right — y decreases while x increases. In a real context it marks decline: falling sales, a downhill road, a cooling temperature.
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