| x1 | y1 | x2 | y2 | Slope | Y-intercept | Equation | Note |
| {y} |
Calculate the Slope of a Line from Two Points
The slope of a line indicates its steepness: how much the y value changes when x increases by 1. From two points A(x₁, y₁) and B(x₂, y₂), this calculator determines the slope, the y-intercept and the equation of the line in the form y = ax + b.
The slope formula
The slope a is calculated with the formula:
a = y₂ − y₁x₂ − x₁
The y-intercept b (the value of y when x = 0) is then derived with:
b = y₁ − ax₁
How to use it
Enter the coordinates of the two points in the corresponding boxes: x₁ and x₂ for the x-coordinates, y₁ and y₂ for the y-coordinates. The slope, the y-intercept and the equation of the line are displayed automatically as you type.
You can also enter values as fractions (for example 1/2 or -3/4) or with a decimal point. To erase all the data, click the Clear button.
Special case: the vertical line
If both x-coordinates are identical (x₁ = x₂), the line is vertical and its slope does not exist: the displayed result is then Undefined.
Keyboard shortcuts
The calculator's keyboard shortcuts help you work faster:
m ⇝ Clear
f ⇝ Save the calculation to the history
Results history
By clicking Save, each calculation is stored in a table showing the resulting equation and the coordinates of the two points. You can then export it in CSV format to use it in a spreadsheet, or in PDF format.
Example calculation
Take the points A(1, 2) and B(3, 6). The slope is a = 6 − 23 − 1 = 42 = 2. The y-intercept is b = 2 − 2 × 1 = 0. The equation of the line is therefore y = 2x.