Equation of a Line Calculator (Free, with Graph)

Use this free equation of a line calculator to find the equation of a line from a slope and a point, or from two points. You’ll get the line in slope-intercept, point-slope, and standard form, plus a graph and the step-by-step working.

How to use it

1. Pick a mode: from a slope & point, or from two points.
2. Enter your values.
3. Read all three forms of the equation and see the line graphed.

The three forms

Slope-intercept: y = mx + b. Point-slope: y − y₁ = m(x − x₁). Standard: Ax + By = C. The calculator converts between them and handles vertical and horizontal lines.

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Frequently asked questions

How do you find the equation of a line from two points?

Find the slope m = (y₂ − y₁)/(x₂ − x₁), then use a point to solve for b in y = mx + b. The calculator shows every step.

What is standard form?

Ax + By = C with integer coefficients and A ≥ 0. The tool converts your line to this form automatically.

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Does it handle vertical lines?

Yes — a vertical line has undefined slope and the equation x = a constant.

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Read the full lesson: learn the method step by step.

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