How many fence posts do I need?

By Ralph · Updated June 18, 2026

For a straight fence, the number of posts is the fence length divided by the post spacing, plus one. A 100 ft fence with posts every 8 ft needs 14 posts (13 sections + 1 end post) — before adding posts for corners and gates.

The formula

Sections = fence length ÷ post spacing, then posts = sections + 1

The "+1" is the end post that closes the last section. Then add one extra post at every corner and a sturdy pair of posts for each gate.

A worked example

  • Fence length: 100 ft, posts every 8 ft
  • Sections: 100 ÷ 8 = 12.5 → round up to 13 sections
  • Posts: 13 + 1 = 14 posts for the straight run
  • Add posts for corners and gates on top of that

Let the calculator count it

Enter your fence length and post spacing into our fence calculator to get posts, panels, and an estimated cost instantly.

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Choosing post spacing

Fence typeCommon spacing
Pre-made panels6 or 8 ft (match the panel)
Wood picket / privacy6–8 ft
Chain linkup to 10 ft

How deep should the posts go?

A fence is only as solid as its posts. The rule of thumb is to set about one-third of the post's total length in the ground — and always below your local frost line, or winter heave will push the posts up and out of line.

Fence heightHole depth
4 ft~24 in
6 ft30–36 in
8 ft36–42 in

Add a few inches of gravel at the bottom of each hole so water drains away from the post end.

Setting a fence post in concrete — cross-section Depth ≥ ⅓ of height Hole ≈ 3× post width Post Concrete ≈6 in gravel
Cross-section of a post set in concrete — resting on ~6 in of gravel, with the concrete crowned above grade to shed water.

Concrete per post

Most posts are set in concrete — about 1–2 bags of fast-setting mix per standard 4×4 post, and 2–4 bags for larger corner or gate posts in wider, deeper holes. Once you know your post count and hole size, size the concrete precisely with our concrete calculator.

Corner, end, and gate posts

Line posts just hold up the fence between them, but corner, end, and gate posts take real load and pull. Size them up — a 6×6 instead of a 4×4 — set them deeper, and use more concrete. Gates are the usual failure point: a gate sags within a season or two if its hinge post isn't rock solid.

Frequently asked questions

How far apart should fence posts be?
6–8 ft for wood picket and privacy fences, the panel width (often 6 or 8 ft) for pre-made panels, and up to 10 ft for chain link.
How deep should a fence post be?
About one-third of the post's total length, and below your frost line — roughly a 24-in hole for a 4-ft fence and 30–36 in for a 6-ft fence.
How many bags of concrete per post?
About 1–2 bags of fast-setting mix for a standard 4×4, and 2–4 bags for larger corner or gate posts.
How many posts for a 100 ft fence?
About 14 at 8-ft spacing (13 sections + 1 end post), plus an extra post per corner and a pair per gate.
Concrete or gravel for the posts?
Concrete is the most rigid and is standard for gate and corner posts; tamped gravel drains well in wet climates and makes posts easier to replace. Add gravel at the hole bottom either way.
Do corner and gate posts need to be bigger?
Yes — size them up, set them deeper, and use more concrete, since they carry far more load than line posts.

Related guides

Written by Ralph, founder of Homestimate. Ralph started the site after one too many mid-project trips back to the hardware store, and builds every calculator and guide here — showing the math so you can check it. About Homestimate · How we estimate