How many posts for 100 feet of fence?

At 8 ft spacing, 13 sections and 14 posts. Spacing above 8 ft lets rails sag; 6 ft is better on windy or sloping ground.

How much concrete per fence post?

Two 50 lb bags per 4×4 post in a 10 in hole about 2 ft deep is the usual rule. Bigger posts, deeper holes below a frost line, and gate posts take more.

How many pickets do I need?

Fence length in inches divided by the picket width plus the gap. A 100 ft privacy fence with 5.5 in boards and no gap needs about 219 pickets.

Fence calculator

Form 52 · Materials estimateFigures checked 2026-09-04

US customary

Measurements

Fence length(ft)

Fence height(ft)

What you need

Quantity · Amount

01Sections at 8 ft100 ft of fence13
02Postsone per section plus one to end the run14$252
03Rails, 3 per section39$351
04Pickets at 5.5 in219$876
05Concrete, 50 lb bagstwo bags per post28 bags$210

Total, materials$1,689

Posts want to be 8 ft long: a third of the height in the ground, below the frost line where it is deeper.
Gates, hinges, latches and fasteners are extra; a gate needs a heavier post on each side.

The material

Post spacing(ft)8 ft standard; 6 ft in wind or on slopes

Rails per sectionTwo for 4 ft fence, three for 6 ft

Picket width(in)A 1×6 board is 5.5 in actual

Gap between pickets(in)0 for privacy; 2–3 in for a picket fence

Prices — put in what you were quoted

Post price($ per each)4×4×8 ft pressure-treated

Rail price($ per each)2×4×8 ft pressure-treated

Picket price($ per each)

Concrete per bag($ per bag)Two 50 lb bags per post is the usual rule

Total, materials14 posts$1,689

Where these figures come from

Post spacing 8 ft, three rails at 6 ft height, two 50 lb bags per post: standard US wood-fence practice.
Prices are typical US lumber-yard figures at the date on this sheet.

Type the total length of fence and the post spacing (8 ft is usual for a wood fence, 6 for windy sites). The sheet counts posts, rails at your number per section, pickets at the width and gap you choose, and the concrete to set the posts.

Worked examples

100 ft of 6 ft privacy fence: 14 — posts, about $1,689 in materials.
60 ft picket fence, 3 in gaps: 9 — posts, about $781 in materials.

How it is worked out

Sections = length ÷ spacing, rounded up. Posts = sections + 1. Rails = sections × rails per section. Pickets = length in inches ÷ (picket width + gap), rounded up. Concrete = posts × 2 bags.

The figures behind it

Post spacing 8 ft, three rails at 6 ft height, two 50 lb bags per post: standard US wood-fence practice.
Prices are typical US lumber-yard figures at the date on this sheet.

Every figure here is an estimate. Materials vary with moisture, compaction and product; order a little extra and confirm quantities with your supplier.

Questions people ask

How many posts for 100 feet of fence?: At 8 ft spacing, 13 sections and 14 posts. Spacing above 8 ft lets rails sag; 6 ft is better on windy or sloping ground.
How much concrete per fence post?: Two 50 lb bags per 4×4 post in a 10 in hole about 2 ft deep is the usual rule. Bigger posts, deeper holes below a frost line, and gate posts take more.
How many pickets do I need?: Fence length in inches divided by the picket width plus the gap. A 100 ft privacy fence with 5.5 in boards and no gap needs about 219 pickets.

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