Slope Calculator — How to Calculate Slope Between Two Points
Calculate slope m = (y₂ − y₁)/(x₂ − x₁) between two points. Example: (1,2) and (3,6) → m = 2. Rejects vertical lines where Δx = 0. Browser learning tool for algebra coursework.
How it works
Enter two distinct points (x₁,y₁) and (x₂,y₂). The tool returns the slope of the line through them. If the x-coordinates match, the slope is undefined and the page shows an error.
Formula
Slope between two points:
- m = (y₂ − y₁) / (x₂ − x₁).
- Positive m rises left→right; negative m falls.
- Δx = 0 means a vertical line — undefined slope here.
- Order of points cancels in the ratio if swapped consistently.
Example
Example: (1,2) and (3,6) → m = (6−2)/(3−1) = 2.
When to use it
- Algebra homework: slope from two points.
- Check rise-over-run before graphing.
- Compare with aspect-ratio ideas of Δy:Δx.
Frequently asked questions
What if x₁ equals x₂?
The slope is undefined (vertical line); this page errors.
Does point order matter?
Swapping both points keeps the same m.
What does m = 2 mean?
For each +1 in x, y increases by 2.
Is a horizontal line allowed?
Yes — then m = 0 when y₁ = y₂ and x differs.
Related tools
Questions or feedback
Something unclear, broken, or missing? Draft a message below — we read every note about these tools.