Fence Calculator

Estimate materials for building a wooden fence including posts, rails, pickets, and concrete. Calculates based on fence length, post spacing, and fence height.

About this Calculator

Estimate materials for building a wooden fence including posts, rails, pickets, and concrete. Calculates based on fence length, post spacing, and fence height.

Formula & Calculations

Formula

Posts = (Fence Length / Post Spacing) + 1; Rails = Posts × Rails per section × (Posts - 1) or Posts × 2; Pickets = Fence Length × 12 / Picket Width × number of sides; Concrete Bags = Posts × 2

Where:

L=Total fence line length in feet
Spacing=Distance between posts in feet (typically 8 ft)
Height=Fence height in feet (typically 4, 6, or 8 ft)

Assumptions

Fence posts are set in concrete (2 bags of 50 lb concrete mix per post).
Standard 3-rail construction with 2×4 rails (three rails per section for 6 ft fence).
Pickets are 5.5 inches wide (standard 1×6 dog-ear picket) with a 0.5 inch gap.
End and corner posts are included in the post count.

Calculation Examples

Example 1

Inputs:Fence: 100 ft long, 8 ft post spacing, 6 ft height

Result:~14 posts, ~36 rails (3-rail), ~200 pickets, ~28 concrete bags

Posts = 100/8 + 1 ≈ 13.5 → 14 posts. Rails = 13 sections × 3 = 39 rails. Pickets = 100×12/6 ≈ 200 (with 5.5" width + 0.5" gap).

Example 2

Inputs:Fence: 50 ft long, 6 ft post spacing, 4 ft height

Result:~10 posts, ~18 rails (2-rail), ~110 pickets, ~20 concrete bags

Posts = 50/6 + 1 ≈ 9.33 → 10 posts. Rails = 9 sections × 2 = 18 rails. Pickets = 50×12/5.5 ≈ 110.

Frequently Asked Questions

How deep should fence posts be set?

A general rule is to bury one-third of the post length. For a 6-foot fence, that means 2 feet in the ground (8-foot post). In frost-prone areas, posts should extend below the frost line.

How many bags of concrete per fence post?

Plan on 1-2 bags of 50-pound fast-setting concrete mix per post for a standard 4×4 post in a 8-10 inch diameter hole. This calculator assumes 2 bags per post.