Equal spacing· 3 min read
Fence Picket Spacing: How Many Pickets per Section and What Gap
A 2 m fence section with 90 mm pickets: how many you need for a gap of at most 20, 30 or 50 mm, where to mark the first one and how to scale it up.
With a picket fence, one thing goes wrong more than anything else: the last gap at the post. Start at one post and keep going with a fixed gap, and at the far end you get either a thin sliver or a gap too narrow for a picket. The fix is simple — work out how many pickets fit first, then derive a gap that is the same everywhere, including at both posts.
What to measure
- The clear width of the section — the distance between the posts (face to face) that the pickets will fill. In the example, 2,000 mm (about 79 in).
- The picket width — measure several real pickets, not the label. In the example, 90 mm.
- The largest gap you want — depending on how much privacy you need and how much wind and view the fence should let through.
How many pickets in a 2,000 mm section
In “Gap must not exceed” mode, the calculator looks for the fewest pickets so that no gap is larger than your limit. The gaps at the posts equal the gaps between pickets, so the section is symmetrical.
| Max gap | Pickets | Actual gap | Centre to centre |
|---|---|---|---|
| 20 mm | 18 | 20 mm | 110 mm |
| 30 mm | 17 | 26.1 mm | 116.1 mm |
| 50 mm | 14 | 49.3 mm | 139.3 mm |
With a 30 mm limit you get 17 pickets and a gap of 26.1 mm (just over 1 in). The actual gap is always equal to or smaller than the limit — the calculator would rather add a picket than break the limit you set.
Why not a fixed 30 mm gap
If you insisted on an exact 30 mm gap, 16 pickets would fit. In “Exact gap” mode the calculator splits the rest between both ends, so you get 55 mm at the posts instead of 30 mm. The section is symmetrical, but the wider gaps at the posts show. With a maximum gap everything is equal — which is why it usually suits a fence better.
Where to mark the pickets
- 1The first picket starts 26.1 mm from the post.
- 2Each next one starts 116.1 mm further on: 142.2 mm, 258.3 mm, 374.4 mm …
- 3The ninth picket sits exactly in the middle of the section — its centre is at 1,000 mm. If that checks out, the first half is right.
- 4The last, seventeenth picket starts at 1,883.9 mm, leaving 26.1 mm at the second post.
Mark every position from one post, not from the previous picket. With 17 pickets, an error of 1 mm per picket would add up to more than 1.5 cm.
Equal spacingOpen this example in the spacing calculatorHow many pickets for the whole fence
If all sections have the same clear width, multiply the picket count by the number of sections. A fence with 10 sections of 2,000 mm and a 30 mm limit needs 170 pickets. Work out narrower sections (by a gate, at a corner) separately — the same limit gives a different count and a slightly different gap, but the difference won't be visible.
It's different when the pickets run in front of the posts and hide them. Then you don't work section by section — enter the full fence length at once. Set the ends depending on whether the fence should finish with a picket (“Elements touch the ends”) or with a gap.
Workshop tips
- Make a spacer exactly the size of the calculated gap — for example an offcut planed to 26 mm. Hold it in place while fixing and use the marks as a check.
- Wood changes size with moisture. Let the pickets acclimatise outdoors before installing and measure their width afterwards.
- If the posts are not perfectly placed, measure the clear width of each section at the top and at the bottom. If they differ, enter the smaller value so the pickets fit.
- Whether a fence needs a permit and how tall it may be is up to your local authority — the calculator only handles the layout.