Slope Calculator

Run divided by rise is the reciprocal of a nonzero finite slope. A horizontal line makes run/rise undefined; a vertical line gives run/rise zero. One point alone does not determine slope: provide another point or an independently known slope.

Enter rise and run, or two points in the same coordinate units. Slope is rise divided by run; percentage gradient is slope × 100. The directed angle runs from −180° to 180° relative to the positive horizontal axis.

m = (y₂ − y₁)/(x₂ − x₁); y − y₁ = m(x − x₁)

Rise 3 and run 4 give slope 0.75, gradient 75% and angle 36.8699°. A vertical line has undefined slope. Identical points do not define a unique line. The graph places the first point at its centre and shows the displacement to the second point.

The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.

Known measurements

Rise and run

Run

4

Rise

3

Primary result: Run divided by rise: 1.3333333.

• Measure from the datum or reference edge described by this tool, and do not mix inside, outside and centerline dimensions.
• Keep inputs in the displayed units and preserve more precision than the final cutting or purchasing tolerance requires.
• When the result is close to a limit, verify it with a test piece, field measurement, manufacturer drawing or qualified project professional.

This is signed line geometry, not a structural, drainage or accessibility design check. Both coordinates must use the same length unit. Reverse point order changes the directed angle by 180° but preserves a nonvertical slope.