Slope Calculator

Change any one value and the others update, with a diagram drawn to scale.

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Grade, angle and ratio

Grade (%)Angle (°)Ratio (1 : n)1 :Per mille (‰)RiseRun

x₁y₁x₂y₂

Grade (%) = rise ÷ run × 100, angle = arctan(rise ÷ run), and in a 1:n ratio n = run ÷ rise.
Edit any of grade, angle, ratio, per mille, rise or run and the rest update instantly. Changing the rise keeps the run and recalculates the slope.
The triangle is drawn in true proportion, so you can see how steep the slope really is.
Enter two points to get the slope m = (y₂ − y₁) ÷ (x₂ − x₁), the angle, the distance, the midpoint and the equation of the line.

Is a 100% grade a vertical wall?

No. A 100% grade means the rise equals the run, which is 45°. Grade and angle are not proportional: a 10% grade is about 5.71°.

What is a 1:12 slope in percent?

One unit of rise for every 12 units of run is about 8.33%, or roughly 4.76°. It is a ratio often quoted for wheelchair ramps.

How do I convert roof pitch like 6/12?

A 6/12 pitch rises 6 for every 12 of run. Enter 6 as the rise and 12 as the run to get a 50% grade, about 26.57°.