The Build Calculator

Fence Calculator

Work out a complete wood fence shopping list: posts by spacing, rails, pickets with your gap, and concrete bags for the post holes — with a cost estimate per linear foot.

Fence materials
posts
rails (8 ft 2×4)
pickets
50 lb concrete bags

Enter a picket price to estimate cost.

You might also need:Concrete Calculator·Board Foot Calculator

Fence material math

posts = ceil(length ÷ spacing) + 1 (+1 per gate)
rails = sections × rails per section · pickets = length ÷ (picket width + gap)
concrete = 2 × 50 lb bags per post

A 100-foot privacy fence at 8-foot spacing needs 14 posts (plus one per gate), 39 rails and about 200 pickets, set with 28 bags of fast-setting concrete. Sloped yards need either stepped or racked sections — buy 5% extra rails and pickets for cuts.

Typical fence specs

FencePostDepthRails
4 ft picket4×4 × 6.5 ft2 ft2
6 ft privacy4×4 × 8–9 ft2.5–3 ft3
8 ft privacy6×6 × 11 ft3 ft4

Build tips

  • Call 811 before digging — free utility marking, required in most states, and post holes hit lines more often than you'd think.
  • Set all posts first, let concrete cure overnight, then string a line and rail the whole run for a straight top.
  • Crown side out: face picket crowns the same way and gap them with a spacer block for even reveals.
  • Prefer round pier footings for gate posts? Size them with the Sonotube calculator; bulk concrete math is in the concrete calculator.

Frequently asked questions

How far apart should fence posts be?+

Set wood fence posts 6 to 8 feet apart on center. Eight feet matches standard rail lengths and minimizes posts; six feet is stiffer for tall privacy fences and windy sites. Chain link can stretch to 10 feet.

How many bags of concrete per fence post?+

Two 50 lb bags of fast-setting concrete per post is typical for a 4×4 post in an 8–10 inch hole 2 feet deep. Bigger 6×6 posts in 12-inch holes take 3–4 bags. This calculator totals it for the whole run.

How deep should fence posts be set?+

Bury one-third of the total post length, minimum 2 feet — a 6-foot fence uses 9-foot posts set 3 feet deep in frost country, or 8-foot posts at 2 feet where freeze isn’t a factor. Always set posts below the frost line.

How many pickets do I need per foot of fence?+

Standard 5½-inch pickets butted tight run 2.2 per linear foot; with a typical ½-inch gap it drops to about 2 per foot. A 100-foot privacy fence needs roughly 200–220 pickets.

How much does a wood fence cost?+

DIY materials for a 6-foot pressure-treated privacy fence run $15–$25 per linear foot; cedar $25–$40. Professional installation doubles it. Gates add $150–$600 each depending on width and hardware.

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