Slope (also called gradient) measures how steep a line is. It equals the vertical change (rise) divided by the horizontal change (run) between any two points on the line: m = (y2 - y1) / (x2 - x1).

What does an undefined slope mean?

When x1 equals x2, the denominator is zero, making the slope undefined. This describes a perfectly vertical line, which has no slope value.

What does a slope of zero mean?

A zero slope means the line is perfectly horizontal — there is no vertical change between the two points, so rise = 0.

How is the angle calculated?

The angle is computed using the arctangent of the slope: angle = arctan(m). The result is expressed in degrees, ranging from -90° to +90°.

What is the y-intercept?

The y-intercept (b) is where the line crosses the y-axis. It is calculated as b = y1 - m * x1, using the slope m and either known point.

What is slope-intercept form?

Slope-intercept form is y = mx + b, where m is the slope and b is the y-intercept. It is the most common way to express the equation of a straight line.

Slope Calculator

Enter two coordinate points and instantly get slope, angle, y-intercept, and the line equation in slope-intercept form.

Enter Two Points

Point 1 (x₁, y₁)

x₁

y₁

Point 2 (x₂, y₂)

x₂

y₂

Quick Examples

Enter two points and click Calculate

Results will appear here

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Summary

The slope calculator finds the slope (gradient) of a straight line passing through two coordinate points. It displays the result as both a simplified fraction and a decimal, computes the angle the line makes with the x-axis, derives the y-intercept, and produces the full line equation in slope-intercept form (y = mx + b). All calculations run instantly in your browser with no data sent to any server.

How it works

Enter the x and y coordinates for your first point (x1, y1).
Enter the x and y coordinates for your second point (x2, y2).
Click "Calculate" or press Enter — results appear instantly.
Slope is shown as a simplified fraction (rise/run) and a decimal.
Angle with the x-axis is computed via arctangent of the slope.
The y-intercept and full slope-intercept equation are displayed.

Use cases

Verify homework answers for algebra and geometry problems.
Find the gradient of a road or ramp given two elevation points.
Determine the slope of a trend line between two data points.
Calculate the angle of inclination for engineering or construction projects.
Derive the equation of a line through two known points.
Check the steepness of a hill using GPS coordinates.
Solve coordinate geometry problems quickly during exam prep.
Understand rise-over-run intuitively with the fraction form.

Frequently Asked Questions

Last updated: 2026-05-29 · Reviewed by Nham Vu