The short answer: a 100 ft aluminum fence with 6 ft panels needs 17 panels and 18 posts. Aluminum fencing works like vinyl: it ships as preassembled panels, one per section between posts. Here is the math.
The formula
sections = run length ÷ panel width, rounded up panels = sections posts = sections + 1, plus one per gate
A 100 ft run divided by 6 ft panels is 16.7, which rounds up to 17 sections. Each section takes one panel, so that is 17 panels. Posts are the 17 sections plus one closing post, giving 18, before gates.
How panel width changes it
Wider panels mean fewer sections and fewer posts. Match the calculation to the panels you are buying, since the post spacing is simply the panel width.
| Panel width | Sections for 100 ft | Posts |
|---|---|---|
| 6 ft | 17 | 18 |
| 8 ft | 13 | 14 |
Gates
Each gate opening replaces a panel and adds a post for the hinge and latch side. So a fence with one gate has one fewer panel and one more post than the plain run. The calculator subtracts the gate width before counting so the panel total stays right.
Get your exact number
Enter the length, height, panel width and any gates in the aluminum fence calculator and it returns the panels, posts and concrete bags. Vinyl panel fences follow the same logic, covered in the vinyl fence guide.