Formula used
Grade (%) = rise ÷ horizontal run × 100; slope angle = arctan(rise ÷ run)
Worked grade example
Grade Calculator example: 1.77 ft ÷ 38.5 ft × 100 = 4.6% grade. The same line is 2.63° and approximately a 1:21.75 rise-to-run ratio.
What the converted result represents
Use percent grade, angle, and ratio as equivalent descriptions of the same straight slope, with direction recorded separately.
Limits of the geometric model
Confusing slope distance with horizontal run, mixing units, measuring too short a baseline, or overlooking local high and low points distorts grade.
Questions specific to this calculation
What does the reported grade percentage mean?
Enter vertical change as rise and horizontal distance as run in the same unit. A negative rise may be used to describe fall when the field accepts it.