Math
Slope Calculator
Enter two points to find the slope, or use a known slope to solve a missing coordinate. mathcheck gives you rise over run, equations, intercepts, grade, midpoint, distance, a graph, and plain-English interpretation.
The x-coordinate of the first point.
The y-coordinate of the first point.
The x-coordinate of the second point.
The y-coordinate of the second point.
Slope
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- Line equation
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- Grade
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- Midpoint
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- Distance
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Student quick launch
Grade planning, algebra checks, and formulas students reach for most.
Study path
Use this calculator with
Follow these when you want the formula behind the answer, a short lesson, or nearby tools in the same topic.
What is slope?
Slope measures how steep a line is. It compares vertical change (rise) to horizontal change (run) between any two points on the line.
What this calculator can solve
| Mode | Use it when | Output |
|---|---|---|
| Slope from two points | You know both ordered pairs | Slope, equations, intercepts, graph, midpoint, distance |
| Find missing y2 | You know P1, x2, and the slope | The missing y-coordinate plus the complete line |
| Find missing x2 | You know P1, y2, and a nonzero slope | The missing x-coordinate plus the complete line |
How to find slope from two points
- Subtract the y-values to find the rise: y2 - y1.
- Subtract the x-values to find the run: x2 - x1.
- Divide rise by run and simplify the fraction.
- Use the slope and one point to write the equation of the line.
How to read the answer
- Positive slope means the line rises from left to right.
- Negative slope means the line falls from left to right.
- Zero slope means the line is horizontal.
- Undefined slope means the line is vertical, so the run is 0.
Line equation forms
This calculator shows slope-intercept form and point-slope form because teachers commonly ask for both. Slope-intercept form is best when you want to see the y-intercept. Point-slope form is fastest when you already know one point and the slope.
Slope as percentage grade
Roads, ramps, roofs, and trails often describe slope as a percentage grade. Multiply the slope by 100 to convert it to a grade. A slope of 0.08 is an 8% grade; a slope of 1.5 is a 150% grade.
Worked examples
Positive slope
Line through (1, 2) and (5, 8)
Slope
3/2 (1.5)
Negative slope
Line through (-2, 7) and (4, -5)
Slope
-2
Find y2
P1 = (1, 2), x2 = 5, slope = 1.5
Slope
3/2 (1.5)
Find x2
P1 = (1, 2), y2 = 8, slope = 1.5
Slope
3/2 (1.5)
Horizontal line
Line through (-3, 4) and (6, 4)
Slope
0
Vertical line
Line through (2, -1) and (2, 5)
Slope
undefined
Frequently asked questions
What does undefined slope mean?+
Undefined slope means the line is vertical. The run is 0, and division by 0 is not defined, so the slope cannot be written as a number.
Is slope the same as rise over run?+
Yes. Rise over run is the visual way to describe slope: how far the line moves up or down divided by how far it moves left or right.
Can slope be negative?+
Yes. A negative slope means the line falls as you move from left to right. For example, a slope of -2 means the line goes down 2 units for every 1 unit to the right.
Which point should be point 1?+
Either point can be point 1. If you swap the two points, both the rise and run change signs, so the slope stays the same.
Can I find a missing coordinate if I know the slope?+
Yes. Choose Find missing y2 or Find missing x2. The calculator rearranges the slope formula to solve for the missing coordinate, then builds the full line from the solved point.
Why can't I find a unique x-coordinate when slope is 0?+
A slope of 0 is a horizontal line. If the y-value is the same, infinitely many x-values work; if the y-value is different, no point on that horizontal line has that y-value.
What is percentage grade?+
Percentage grade is slope multiplied by 100. It is commonly used for ramps, roads, trails, and roofs. A slope of 0.12 is a 12% grade.
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Last updated: May 5, 2026