Math
Instant, private, and free
Point-Slope Form Calculator.
Build a line equation from a point and slope.
Set your values
Results update as you type.
Results update automatically as you type.
Use Cases
Quickly write line equations for homework
When you have a point and slope, this calculator gives you the equation instantly, saving time and reducing errors.
Example: Given point (2,3) and slope 4, get y - 3 = 4(x - 2).
Check your algebra work
Verify that the equation you derived manually is correct by comparing it with the calculator's output.
Example: Check if your equation matches for point (-1,5) and slope -2.
Frequently Asked Questions
- What is the point-slope form of a line?
- The point-slope form is y - y₁ = m(x - x₁), where (x₁, y₁) is a point on the line and m is the slope. It's useful when you know one point and the slope.
- How do I use this calculator?
- Enter the x-coordinate (x₁) and y-coordinate (y₁) of a point on the line, and the slope (m). The calculator will output the equation in point-slope form.
- Can I use this calculator for vertical lines?
- No, vertical lines have an undefined slope, which cannot be entered. For vertical lines, use the equation x = constant.
Tips & Common Mistakes
Tips
- Ensure the slope is entered as a decimal or fraction. For fractions, use the division symbol (e.g., 3/4).
- Double-check that the point coordinates are correct; a small typo can change the entire equation.
- Remember that the point-slope form can be converted to slope-intercept form (y = mx + b) by solving for y.
- If the slope is zero, the line is horizontal, and the equation simplifies to y = y₁.
Common Mistakes to Avoid
- Mixing up the order of x₁ and y₁ when entering coordinates.
- Entering the slope as a percentage instead of a decimal or fraction.
- Forgetting that the point-slope form uses subtraction: y - y₁ = m(x - x₁), not addition.
Last updated: August 13, 2026