Measurement
Construction Slope Calculator
Rise, run, percent grade, ratio and angle — enter any one and get the others.
Grade
percent
- Ratio
- 10:110 of run per 1 of rise
- Angle
- 5.71°
- Rise
- 6ft
- Run
- 60ft
- Slope length
- 60.3ftAlong the face.
The working
Grade = Rise ÷ Run × 100
= 6 ÷ 60 × 100
= 10%
Angle = atan(Rise ÷ Run)
= atan(6 ÷ 60)
= 5.71°
Slope length = √(Rise² + Run²)
= √(6² + 60²)
= 60.3 ft
The distance along the face — longer than the run, and the length you buy material for.
A site talks about the same slope four different ways. Drainage is specified in percent, a batter in a ratio, a ramp in rise and run, and a survey in degrees. Enter whichever you have and the calculator gives the rest, plus the length along the face, which is the figure that catches people out when they order pipe, fabric or seed for a bank.
How this calculator works
- Formula version
- 1.0.0
- Last reviewed
- 2026-09-01
- External data
- None
This tool uses only your inputs and exact unit conversions. No benchmark, average or market figure is built into it. How we calculate
What this calculates
Given any one description of a slope, the other three. Rise over run is the two measurements; percent is rise per hundred of run; the ratio is run per one of rise; the angle is degrees from horizontal. They are all the same fact.
The relationships
Percent grade is rise ÷ run × 100. The ratio H:1 is run ÷ rise, so a 2:1 batter rises one for every two of run. The angle is the arctangent of rise ÷ run. Each converts exactly into the others — there is nothing approximate anywhere in this.
Slope length is the hypotenuse, √(rise² + run²). It is always longer than the run, and it is the length you measure along the surface — the one that matters when buying anything laid on the bank.
Run is horizontal
The run is the distance between the two ends measured flat, as on a plan, not along the ground. Measuring along the surface and calling it the run understates the grade. If you only have the along-surface distance and the rise, the run is √(length² − rise²).
Worked example
A driveway rising 6 ft over a 60 ft run
- Rise
- 6 ft
- Run
- 60 ft
- Grade= 6 ÷ 60 × 100= 10%
- Ratio= 60 ÷ 6= 10 : 1
- Angle= atan(6 ÷ 60)= 5.71°
- Slope length= √(6² + 60²)= 60.30 ft
- A straight, uniform slope between two points.
- Run is the horizontal distance, not the distance along the surface.
- Angle is measured from horizontal.
- It does not model a slope that changes grade along its length — split it into segments.
- It does not say what grade is appropriate for a purpose. Drainage minimums, ramp maximums and stable batter angles are set by codes, materials and soil, not by trigonometry.
- It does not calculate the volume of a slope. The cut and fill calculator does that.
Common questions
- What is a 2% slope in inches per foot?
- A 2% grade rises 2 ft in 100 ft, which is 0.24 in per foot — just under a quarter inch. Enter 2 in percent mode with a run of 1 ft and the rise shows directly.
- What angle is a 1:1 slope?
- Exactly 45°, and exactly 100% grade. Beyond that a slope is usually described by its ratio or angle, because percentages above 100 stop being intuitive.
- Why is the slope length longer than the run?
- Because the run is measured flat and the slope length is measured along the incline. The two are the legs and hypotenuse of a right triangle. Order material by the run and you come up short.
Where people go next
All measurement tools →Ordered by what usually comes next in the same job, not by keyword.