How is the slope of a line calculated?

Slope (m) = (y₂ − y₁) ÷ (x₂ − x₁) — the change in y divided by the change in x between the two points, sometimes called rise over run.

What happens with a vertical line?

If x₂ equals x₁ the run is zero, so the slope is undefined. The calculator reports this rather than dividing by zero.

Is any data sent anywhere?

No — all of the maths runs locally in your browser and nothing is uploaded.

How do I find the equation of a line from two points?

First find the slope m = (y₂ − y₁) ÷ (x₂ − x₁), then the y-intercept b = y₁ − m·x₁. The line is y = mx + b. For (1,2) and (4,8) that is y = 2x + 0.

What does a slope of zero mean?

A slope of zero means the line is horizontal — y does not change as x changes. Its equation is simply y = b, a constant.

How do I convert a slope to an angle?

Take the inverse tangent of the slope: angle = arctan(m), in degrees. A slope of 1 is 45°, and a slope of 2 is about 63.43°.

Slope Calculator — Gera Tools

Slope of a line through two points

The slope (or gradient) measures how steeply a line rises or falls between two points. This tool returns the slope, the line equation and the line’s angle — for students, surveyors and anyone working with linear graphs or gradients.

How it works

The slope is the change in y divided by the change in x, often called “rise over run”:

m = (y₂ − y₁) ÷ (x₂ − x₁)

From the slope and one point, the y-intercept is b = y₁ − m × x₁, giving the line equation y = mx + b. The angle of the line is atan2(Δy, Δx) converted to degrees. A positive slope rises left to right, a negative slope falls, a slope of 0 is horizontal, and a vertical line has an undefined slope because the run is zero — the tool reports this rather than dividing by zero.

Example

For the points (1, 2) and (4, 8):

Result	Value
Δy / Δx	6 ÷ 3
Slope (m)	2
Equation	y = 2x + 0
Angle	≈ 63.43°

All calculations run in your browser, with nothing uploaded.