How many fence panels for 100 feet?
A 100 foot fence run needs 13 panels and 14 posts, using the common default of posts spaced 8 feet apart center to center. 100 divided by 8 is 12.5, which rounds up to 13 spaces, and a straight run always has one more post than it has spaces.
Change the spacing and the count changes with it: tighter spacing means more panels for the same 100 feet, wider spacing means fewer. The full arithmetic for several common spacings is below.
The formula
This is the exact post-count formula used by this site's fence calculator for a straight, contiguous run with a post only at each end: divide the run length by the post spacing, round up to a whole number of spaces, then add one more post for the starting end. Panels equal posts minus one, since one panel fills each gap between two consecutive posts.
100 feet at 8 foot spacing, step by step
| Run length | 100 ft |
| Post spacing | 8 ft (the fence calculator's default) |
| Spaces | 100 ÷ 8 = 12.5, rounded up to 13 spaces |
| Posts | 13 + 1 = 14 posts |
| Panels | 14 − 1 = 13 panels |
These are the exact default values the fence calculator shows for a 100 foot run at 8 foot post spacing, so you can check them against your own screen.
100 feet at other common spacings
The panel count for the same 100 foot run changes with the spacing you pick. Here is the same formula run at three common spacings:
| Post spacing | Spaces (100 ÷ spacing, rounded up) | Posts | Panels |
|---|---|---|---|
| 6 ft | 100 ÷ 6 = 16.67, rounded up to 17 | 18 | 17 |
| 8 ft | 100 ÷ 8 = 12.5, rounded up to 13 | 14 | 13 |
| 10 ft | 100 ÷ 10 = 10 | 11 | 10 |
Not sure which spacing to use? See how far apart should fence posts be for the sourced spacing recommendation.
Buying pre-built panels instead of setting your own spacing
If you are buying fixed-width fence panels rather than choosing your own post spacing, the panel width fixes the spacing for you, and the math flips slightly: panels come first, then posts.
| 6 ft panels | 100 ÷ 6 = 16.67, rounded up to 17 panels, plus 1 = 18 posts |
| 8 ft panels | 100 ÷ 8 = 12.5, rounded up to 13 panels, plus 1 = 14 posts |
At 8 feet, the panel-width method and the post-spacing method land on the same 13 panels and 14 posts, because the panel width and the post spacing are the same number in that case. Run your own run length and spacing in the fence calculator.
What these counts do not include
This is straight-run math only: one continuous line of fence with a post at each end. Every corner where the fence changes direction needs its own additional post, and every gate opening needs a post on each side of it, on top of the 14 posts and 13 panels above. Measure and calculate each straight section of a multi-sided layout separately, then add corner and gate posts based on your own site plan.
Frequently asked questions
How many fence panels does a 100 foot fence need?
With posts spaced 8 feet apart, a 100 foot run needs 13 panels. 100 divided by 8 is 12.5, rounded up to 13 spaces, and each space is one panel.
How many posts does a 100 foot fence need?
14 posts. A straight run always has one more post than it has spaces, so 13 spaces plus 1 equals 14 posts.
Does the panel count change with a different post spacing?
Yes. The count depends entirely on the spacing you choose. At 6 feet, a 100 foot run needs 17 panels and 18 posts. At 8 feet, it needs 13 panels and 14 posts. At 10 feet, it needs 10 panels and 11 posts. Tighter spacing always means more panels and more posts for the same length.
What if I am buying pre-built 6 foot or 8 foot fence panels instead of setting my own post spacing?
Switch to panel-width math: panels equal the run length divided by panel width, rounded up, and posts equal panels plus 1. For a 100 foot run with 6 foot panels, 100 divided by 6 is 16.67, rounded up to 17 panels, plus 1 for 18 posts. With 8 foot panels, 100 divided by 8 is 12.5, rounded up to 13 panels, plus 1 for 14 posts, the same result as the post-spacing method because the panel width and post spacing are the same number in that case.
Do corners and gates add to these counts?
Yes, on top of the straight-run numbers above. Every corner needs its own post, and every gate opening needs a post on each side of it. These panel and post counts only cover one continuous straight section with a post at each end.