Slope-Intercept Form Calculator (y = mx + b)
Find the slope between two points as an exact fraction, plus the y-intercept, slope-intercept and point-slope forms, distance with a simplified radical, midpoint and angle of incline — with steps.
Result
This page opens the slope calculator with the slope-intercept card put first: enter two points and the tool derives the full equation y = mx + b. For (1, 2) and (4, 8) it computes m = (8 − 2)/(4 − 1) = 2 and b = 2 − 2·1 = 0, so the line is y = 2x.
Both coefficients are exact: the slope is a reduced fraction and the intercept comes from b = y₁ − m·x₁ carried out in fraction arithmetic, so points with decimal coordinates produce answers like y = (3/2)x − 1/4 rather than rounded approximations. The substitution steps for m and b are written out one per line.
Slope-intercept form is the version you graph from and the one most homework answers expect: m tells the steepness and b marks where the line crosses the y-axis — the run also reports that crossing point, the point-slope form, midpoint and distance from the same pair of points. If your two points share an x-coordinate, the tool honestly reports an undefined slope and gives the vertical line x = c instead.