Why is the section not exactly 8 ft of boards?

Because post spacing is measured centre to centre, and the posts themselves occupy some of that span. The clear gap between two posts is the spacing minus one post width, which is what the boards actually have to cover.

What if my last section is shorter?

It nearly always is, and that is normal. Most runs do not divide evenly by the spacing, so one bay ends up short. Put it at a less visible end if you can, and keep the boards at the same spacing rather than fanning them out to fill.

Does the picket width change the section count?

It changes the boards per section but not the number of sections. Narrower 1x4 boards need noticeably more of them and more fasteners, which is why a fence that looks similar can cost meaningfully more to build in the narrow board.

Fence Ledger

How many pickets are in an 8 ft fence section?

One section is the unit people build in, so it is the number worth knowing before you order anything: multiply it out and you have the whole fence.

Pickets per section

Boards to fill one bay. Add a waste allowance when you order for the whole fence, not per section.

What the usual answer misses

The gap between boards is doing more work in this calculation than most people expect. A quarter-inch gap on a 5.5 inch board is not a rounding detail — across a section it removes a board roughly every twenty, and across a long fence that is a bundle. The gap exists because timber swells when it is wet, and boards butted tight in dry weather will cup or push each other loose later.

Work out your own

Every assumption above is editable. Change the length, the spacing, the hole size — the numbers and the working update as you go.

Units

Shape

Fence length

Height

Gates

Advanced options

These are typical values, not requirements. Post depth in particular is governed by your local frost line and building code — check before you dig.

Post spacing

Gate width

Picket gap

Hole diameter

Hole depth

Gravel base

Bag yield

Waste allowance

Posts

Sections

Pickets

Concrete

5 bags

Estimated cost

Materials only (DIY)

$264 – $760

Professionally installed

$400 – $1,040

National planning ranges compiled from published US construction cost guides, last checked September 2026 (confidence: medium-low). Prices vary sharply by region, season and contractor. These are estimates for planning, not quotes.

Sources: homeguide.com, calcsummit.com, angi.com, ergeon.com, homewyse.com

Shopping list

Bill of materials for this fence
Material	Size	Quantity
Posts	4x4	3
Rails incl. waste	2x4	4
Pickets incl. waste	1x6	10
Concrete mix		5bags
Gravel		2bags
Exterior screws		≈80
Walk gate kit		1

Why these numbers

How we got the section count

Run 1: 4 ft ÷ 8 ft = 0.5, rounded up to 1 section

How we got the post count

3 posts are fixed by the shape itself
2 at the open ends
1 carrying a gate
0 line posts spaced between them
3 posts in total

How we got the picket count

Each picket covers 5.5 in plus a 0.25 in gap, so they repeat every 5.75 in
4 ft of fence needs 9 pickets
Plus 10% for offcuts, rounded up to 10

How we got the concrete

Each 10 in hole is 30 in deep, less 4 in of gravel base, leaving 26 in of concrete
The 4x4 post itself takes up part of that, so each hole needs the remainder
Across 3 posts
Divided by the 0.6 cu ft a bag yields: 4.99, so buy 5 bags

Common questions

Why is the section not exactly 8 ft of boards?: Because post spacing is measured centre to centre, and the posts themselves occupy some of that span. The clear gap between two posts is the spacing minus one post width, which is what the boards actually have to cover.
What if my last section is shorter?: It nearly always is, and that is normal. Most runs do not divide evenly by the spacing, so one bay ends up short. Put it at a less visible end if you can, and keep the boards at the same spacing rather than fanning them out to fill.
Does the picket width change the section count?: It changes the boards per section but not the number of sections. Narrower 1x4 boards need noticeably more of them and more fasteners, which is why a fence that looks similar can cost meaningfully more to build in the narrow board.