Free 100% In-Browser Tool

Fence Calculator for Posts, Rails, Pickets & Concrete Bags

Estimate fence posts, horizontal rails, vertical pickets, and concrete bags for wood privacy fences.

Quick Answer:To calculate fence materials: divide perimeter by post spacing (usually 8 ft) to get posts (+1 for end), multiply sections by 3 for rails, and divide length by picket width plus gap.

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How to Use the Fence Calculator (Posts, Rails, Pickets & Concrete)

1Enter the total fence perimeter or run length in feet.
2Select your post spacing (8 feet is standard; 6 feet for high-wind areas).
3Select the fence height (6 ft standard privacy, 4 ft garden/picket).
4Review the total count of posts, rails, pickets, and 50-lb concrete bags.

Formula & How It Works

American Fence Association (AFA) Framing Standards

Posts = ⌈L / 8⌉ + 1, Pickets = ⌈L / ((5.5 + 0.5) / 12)⌉

Sections = ⌈Length / Spacing⌉. Posts = Sections + 1. Rails = Sections × (3 for 6ft, 2 for 4ft). Pickets = ⌈Length / (Picket Width + Gap)⌉ × 1.05. Concrete = Posts × 2 bags.

Worked Examples

100-foot Privacy Fence (6 ft High)

Input: 100 ft run, 8 ft post spacing, 6 ft height, 5.5" pickets

Explanation: 100 / 8 = 13 sections (rounded up). Posts = 13 + 1 = 14. Rails = 13 × 3 = 39. Pickets with 1/2" gap = ~210.

Result: 14 posts, 39 rails, ~210 pickets, 28 concrete bags (50-lb)

60-foot Garden Fence (4 ft High)

Input: 60 ft run, 8 ft spacing, 4 ft height

Explanation: 4 ft height uses 2 horizontal rails per section instead of 3.

Result: 9 posts, 16 rails, ~126 pickets, 18 concrete bags

160-foot Backyard Enclosure

Input: 160 ft run, 8 ft spacing, 6 ft height

Explanation: Standard residential property line enclosure material breakdown.

Result: 21 posts, 60 rails, ~336 pickets, 42 concrete bags

Frequently Asked Questions

How many bags of concrete do I need per post?▼

Standard practice is two 50-lb bags of fast-setting concrete per 4x4 fence post hole (one bag for lightweight garden fences).

How deep should fence post holes be?▼

At least one-third to one-half the above-ground height (e.g. 24 to 36 inches deep for a 6-foot fence, and below the local winter frost line).

Why are 3 rails recommended for 6-foot fences?▼

Three horizontal rails prevent cedar and treated pine pickets from twisting and cupping due to sun exposure and rain.

What is the standard gap between pickets?▼

A 1/4 to 1/2 inch gap accommodates wood expansion and allows airflow, while shadowbox fences overlap pickets on alternating sides.

Can I use this for chain link or vinyl fences?▼

This tool is tailored for wood privacy fences. Chain link and vinyl systems have specific modular bracket specifications.

Are my measurements stored?▼

No, all estimates are calculated locally in your browser memory.

Quick Reference & Conversion Table

Fence Length	Post Spacing	Posts Needed	Rails (6ft height)	Pickets (5.5")	Concrete Bags
50 ft	8 ft	8 posts	21 rails	105 pickets	16 bags
100 ft	8 ft	14 posts	39 rails	210 pickets	28 bags
150 ft	8 ft	20 posts	57 rails	315 pickets	40 bags
200 ft	8 ft	26 posts	75 rails	420 pickets	52 bags

⚠️ Common Pitfalls to Avoid

•Using only 2 rails on a 6-foot privacy fence, which leads to warped pickets over time.
•Setting post holes too shallow; post holes must extend below local frost lines (typically 1/3 of post length).
•Forgetting the terminating end post (posts = sections + 1).

💡 Practical Real-World Uses

•Residential property line privacy fence construction.
•Dog runs, livestock enclosures, and garden perimeter protection.
•Contractor cost takeoff and lumber yard ordering.

6-foot Post Spacing vs 8-foot Post Spacing

✓8-foot spacing is the North American residential standard, minimizing post hole digging and concrete costs.
✓6-foot spacing provides superior structural resistance in high-wind regions and reduces rail sagging under heavy wet snow.

Last reviewed & updated: 2026-11-01

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