Algebra

Slope Calculator — Two-Point Line Calculator

Enter two coordinate points to find the slope, full line equation, angle of incline, distance between the points, and their midpoint.

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📌 Enter Two Points

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Enter two points to calculate the slope
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Disclaimer: This tool performs standard mathematical calculations for educational and reference purposes. Always double-check results independently for graded coursework, exams, or safety-critical applications.

What Slope Represents

Slope measures the steepness and direction of a line — how much y changes for every unit change in x. A positive slope rises left to right, a negative slope falls, a slope of zero is a flat horizontal line, and a vertical line has an undefined slope (since it would require dividing by zero).

The Formula

m = (y₂ − y₁) / (x₂ − x₁). Once you have the slope, the full line equation in slope-intercept form is y = mx + b, where b (the y-intercept) is found by substituting either point back into the equation.

Worked Example

Find the line through (1, 2) and (4, 11).

  1. Step 1: m = (11 − 2) / (4 − 1) = 9 / 3 = 3
  2. Step 2: Using point (1,2): 2 = 3(1) + b, so b = 2 − 3 = −1
  3. Step 3: Line equation: y = 3x − 1

Frequently Asked Questions

Slope is rise over run — change in y divided by change in x. For a vertical line, x never changes, so the formula requires dividing by zero, which is mathematically undefined. A horizontal line is the opposite case: y never changes, giving a slope of exactly zero, not undefined.
A negative slope means the line falls as you move left to right — y decreases as x increases. The steeper the negative number, the more sharply the line drops.
The angle (in degrees) is the arctangent of the slope: angle = arctan(m) × (180/π). A slope of 1 corresponds to a 45° angle, since arctan(1) = 45°.
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