Calculator inputs
Choose one input method. Large screens show three columns, smaller screens show two, and phones show one.
Example data table
| Method | Inputs | Angle | Grade | Note |
|---|---|---|---|---|
| Rise and run | Rise 5, Run 12 | 22.619865° | 41.666667% | Classic right triangle example. |
| Two points | (0,0) to (10,4) | 21.801409° | 40.000000% | Useful for geometry and coordinate graphs. |
| Percent grade | 8.5% with run 100 | 4.857888° | 8.500000% | Common for ramps, roads, and drainage. |
| Length and height | Length 13, Rise 5 | 22.619865° | 41.666667% | Starts from the sloped side and height. |
Formula used
From rise and run: angle = arctan(rise / run)
Use this when vertical change and horizontal distance are both known.
From two points: slope m = (y2 - y1) / (x2 - x1), then angle = arctan(m)
This converts a line on a coordinate plane into its incline angle.
From grade percent: angle = arctan(grade / 100)
A grade of 10% means 10 units of rise for every 100 units of run.
From length and height: angle = arcsin(rise / slope length)
This is ideal when the sloped edge and vertical height are measured directly.
Conversions: radians = degrees × π / 180, percent grade = tan(angle) × 100
These outputs help compare slope, angle, and ramp steepness in one place.
How to use this calculator
- Select the method that matches your available measurements.
- Enter values in the visible input boxes. Keep units consistent.
- Press Calculate incline to show the result above the form.
- Review degrees, radians, slope, grade, rise, run, and slope length.
- Use the export buttons to save the result as CSV or PDF.
- Compare your numbers with the example table if you want a quick validity check.
Frequently asked questions
1. What is an incline angle?
It is the angle a line or ramp makes with the horizontal. A larger angle means a steeper incline, while zero degrees means a flat surface.
2. What is the difference between slope and angle?
Slope is a ratio of rise to run. Angle is the geometric tilt measured in degrees or radians. They describe the same steepness in different ways.
3. Can I use negative values?
Yes. Negative rise, grade, or angle indicates a downhill direction. The calculator keeps that sign so you can distinguish descending and ascending lines.
4. Why does a vertical line show an extreme result?
A vertical line has zero run, so slope becomes infinite. The angle approaches 90 degrees, which represents the steepest possible incline from horizontal.
5. Should all measurements use the same unit?
Yes. Rise, run, and slope length should use matching units. The angle stays correct only when the compared lengths are measured on the same scale.
6. When is percent grade more useful than degrees?
Percent grade is common in roads, ramps, drainage, and civil work. Degrees are often easier for geometry, trigonometry, and line analysis.
7. What does “run per 1 rise” mean?
It shows how much horizontal distance is needed for one unit of vertical change. Lower values mean a steeper incline, and higher values mean a gentler one.
8. Can I export the calculated result?
Yes. After calculation, use the CSV button for spreadsheet-friendly output or the PDF button for a portable report you can share or archive.