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Construction & Materials

Wood Fence Calculator

Posts, rails & pickets
Concrete bags
Cost estimate
Fence DetailsFree - Instant

How Fence Materials Are Calculated

Posts equal linear feet divided by post spacing, plus one end post. Rails equal the number of spans (posts minus 1) multiplied by rails per span. Pickets are calculated based on picket width plus gap, covering the full linear footage.

Posts = ceil(length ÷ spacing) + 1
Rails = (posts − 1) × rails per span
Pickets = ceil(length × 12 ÷ picket width)

Who Is This Calculator For?

Wood fencing projects require coordinated counts of posts, rails, and pickets along with concrete for footings. This calculator handles all three material types for five common fence styles so you can build a complete material list before visiting the lumber yard.

Homeowners
Plan a backyard privacy or picket fence and know exactly what to buy at the lumber yard.
Fencing Contractors
Quickly generate material lists for residential and light commercial fencing bids.
Property Developers
Estimate perimeter fencing costs across multiple lots before finalizing a site budget.
DIY First-Timers
Understand how many posts, rails, and pickets a fence requires before starting the project.
Farm Owners
Calculate split-rail or board-on-board material quantities for field or pasture fencing.
Real Estate Investors
Price out curb-appeal fencing before listing a property or planning a renovation.

When Should You Use It?

  • Before buying posts, rails, and pickets at the lumber yard
  • When comparing material costs between fence styles (privacy vs. picket vs. split rail)
  • Getting a concrete bag count for post footings before digging
  • Verifying a fencing contractor's material list before approving a quote
  • Planning a phased fencing project to break purchasing across multiple weekends

Example Calculations

Example 1: 150 ft 6-ft privacy fence, 8 ft post spacing

Posts: ceil(150 ÷ 8) + 1 = 20 posts
Rails: 19 spans × 2 rails = 38 rails
Pickets: ceil(150 × 12 ÷ 5.5) = 327 pickets
Concrete: 20 posts × 2 bags = 40 bags
At $12/post + $8/rail + $3/picket: total = $1,525

Example 2: 80 ft picket fence, 6 ft post spacing

Posts: ceil(80 ÷ 6) + 1 = 15 posts
Rails: 14 spans × 2 rails = 28 rails
Pickets: ceil(80 × 12 ÷ 7) = 138 pickets
Concrete: 15 posts × 2 bags = 30 bags
At $12/post + $8/rail + $3/picket: total = $818

Common Mistakes to Avoid

!
Not accounting for gates: each gate requires two gate posts, which are additional to the standard line posts in your count
!
Buying posts the same height as the fence: posts must be 2–3 ft longer than fence height to allow for burial in concrete
!
Setting posts in dirt without concrete: posts in soil alone will lean within one or two seasons, especially in clay or wet soil
!
Spacing posts more than 8 ft apart for 6-ft privacy panels: longer spans cause rails and panels to sag and rack
!
Buying green (freshly milled) lumber: it shrinks as it dries and leaves visible gaps in privacy fences within the first year

Frequently Asked Questions

For 8-foot post spacing (the most common), divide linear feet by 8 and add 1 for the end post. A 100-foot fence needs 13-14 posts. For 6-foot spacing (recommended for heavier privacy fences), divide by 6 and add 1. Corner posts and gate posts are typically counted as additional posts in the total.

More Construction Calculators

Sources & References

1
American Fencing Association (AFA)
Fence installation guidelines, post spacing standards, and material recommendations for wood fencing.
2
International Building Code (IBC) Section 105.2
Permit requirements, fence height limits, and property line setback regulations for residential fencing.
3
USDA Forest Products Laboratory
Decay resistance ratings for cedar, redwood, and pressure-treated pine used in outdoor fencing applications.
HR
Hassaan Rasheed
Developer and Researcher, CalculatorFlux

Researches and verifies the formulas, methodology, and source data behind each calculator on CalculatorFlux. All tools are built and checked against the cited references before publication.

Last updated: May 2026
Post Depth Guide
Fence HeightPost Length
4 ft fence7 ft post
5 ft fence8 ft post
6 ft fence9 ft post
8 ft fence12 ft post
Posts buried 2-3 ft deep in concrete
Pro Tip
In cold climates, set posts below the frost line to prevent heaving. In zones 5-6 (midwest/northeast), that means burying posts at least 36-42 inches. Heaved posts are the most common cause of fence leaning and failure within the first 5 years.
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