How to use the fence panel stepping on a slope calculator
- Choose Stepped for level panels that step up or down, or Racked for panels that follow the slope.
- Enter the horizontal run of the fence, the total rise (negative if the ground falls) and the widest panel you can use.
- Enter the fence height above the ground, and the post depth in More options if you want full post lengths.
- Read the number of panels, the step per panel, the racked panel length and the table of posts.
Formula
Panels = run / panel width, rounded up; width of each = run / panels
Slope = rise / run; step per panel = width x slope
Racked panel length = width / cos(atan(slope)); rake angle = atan(slope)
Stepped post length = fence height + step on the lower side + depth in the ground
The sum of the steps equals the total rise, which the page shows as a check. A level panel is set at the height of its higher end, so the gap under the lower end is up to one step.
A 40 foot run rising 3 feet
A fence line with a run of 480 inches and a rise of 36 inches, using panels up to 96 inches, needs 5 panels, each 96 inches wide. The slope is 7.5 percent, which is 4.29 degrees, and each stepped panel rises 7.2 inches. Racked panels are 96.27 inches long. With a 72 inch fence, the stepped posts are 79.2 inches long and the racked posts 72 inches.
On a downhill run of 384 inches falling 48 inches, using 96 inch panels, there are 4 panels, each stepping down 12 inches, and the slope is 12.5 percent or 7.13 degrees. The posts after the first are 84 inches, which is the 72 inch fence plus the 12 inch step.
Stepped or racked
Stepped panels stay level and are set at a new height at each post, which leaves a wedge-shaped gap under each panel on a slope. They suit rigid panels such as solid wood or vinyl. Racked panels tilt to follow the ground, so the fence top follows the land. They suit pickets and flexible panels that can be adjusted in the frame. Many panels allow only a small amount of racking, so check what the panel maker allows.
For material counts of a fence see the fence calculator. Other slope and layout tools include the stair stringer calculator, the roof pitch calculator and the nominal to actual lumber size converter.
When the ground is not a straight slope
This tool assumes an even slope between the first and last post. For uneven ground, measure the rise at each post, treat each stretch as its own slope, and run the calculator once for each. Lay out the posts before you dig, since a small error in post height adds up over the run.
Assumptions and limits
- The ground rises or falls evenly from the first post to the last, and the run is the level distance.
- Panels are all the same width, no wider than the width you enter.
- Stepped panels are placed so each one clears the higher ground under its two ends.
- Local rules on fence height, setbacks and permits are not covered.
Frequently asked questions
How do I fence a sloped yard?
Divide the run into equal panels, find the step by multiplying the panel width by the slope, and either step each panel up or tilt (rack) the panels to follow the ground. Cut posts to match the style you pick.
How much should each panel step?
The step is the panel width times the slope. A 96 inch panel on a 7.5 percent slope steps 7.2 inches. The steps over the whole run always add up to the total rise.
How long is a racked panel?
It is the level width divided by the cosine of the slope angle. On a 4.29 degree slope a 96 inch panel is 96.27 inches along its length, so the difference is small on gentle slopes.
What if the slope goes down?
Enter a negative rise. The steps then go down, and each stepped panel is set at the height of its higher, uphill end, so the posts on the downhill side are taller.