Fence Calculator

How to Use This Fence Calculator

1. Measure the total linear feet of fencing needed by walking your property line with a tape measure or measuring wheel
2. Select your desired fence height based on privacy needs and local building codes
3. Choose post spacing (8 feet is standard for most residential fences, 6 feet for high-wind areas)
4. Select your picket board width based on the lumber available at your local supplier
5. Choose 2 or 3 rails per section (3 rails is strongly recommended for 6-foot and taller fences)
6. Review the complete materials list including posts, pickets, rails, and concrete

Remember to check with your local building department about permit requirements, property setback rules, and maximum fence heights before purchasing materials.

What is a Fence Calculator?

A fence calculator is a planning tool that estimates all materials needed for building a wood fence from scratch. Building a fence involves more components than most homeowners realize: vertical posts set in concrete, horizontal rails connecting the posts, vertical picket boards creating the fence face, and fasteners holding everything together.

By calculating materials in advance, you avoid multiple trips to the lumber yard during your project and ensure you have matching materials from the same lot. The calculator accounts for the 10% waste factor that professionals recommend for cutting mistakes, warped boards, and damaged pieces. Having a complete materials list also helps you compare prices between suppliers and plan your budget accurately.

Choosing the Right Fence Height

Fence height affects both materials needed and functionality:

• 4-foot fence: Ideal for decorative front yard fencing and defining property boundaries without blocking views. Often used for picket fence styles
• 6-foot fence: The most common privacy fence height. Provides good privacy while remaining within most residential building codes. Standard for backyards
• 8-foot fence: Maximum privacy and security. May require permits and has stricter wind load requirements. Often used near busy roads or commercial properties

Fence Post Spacing and Materials

Post spacing affects fence strength and material costs:

• 6-foot spacing: Creates the strongest fence. Recommended for tall fences, windy areas, and security applications. Uses more posts but provides superior stability
• 8-foot spacing: The standard for residential privacy fences. Balances strength with material efficiency. Works well with 8-foot rail boards
• 10-foot spacing: Suitable only for decorative or lightweight fences. Reduces material costs but may sag over time

Always use pressure-treated lumber rated for ground contact (UC4A or higher) for fence posts. Posts should be 4x4 minimum for fences up to 6 feet, and 6x6 for 8-foot fences.

Fence Calculation Formulas

The calculator uses these industry-standard formulas:

Posts = (Fence Length / Post Spacing) + 1

Sections = Posts - 1

Pickets = (Fence Length x 12 / Picket Width) x 1.10

Rails = Sections x Rails Per Section

Concrete = Posts x 2 bags (50 lb each)

Post Hole Guidelines

Proper post installation is critical for fence longevity:

• Hole depth: Bury 1/3 of the total post length, typically 24-30 inches for most fences
• Hole diameter: Dig holes 3 times the post width (12 inches for 4x4 posts)
• Concrete: Use 2 bags of 50-pound fast-setting concrete per post
• Drainage: Add 4 inches of gravel at the bottom of each hole before setting the post
• Setting: Check level and plumb before concrete sets. Brace corner and gate posts until fully cured

Additional Materials Checklist

Beyond the main components, you'll need these supplies:

• Galvanized or stainless steel screws (3-inch for rails, 1.5-inch for pickets)
• Post caps to prevent water damage and extend post life
• Gate hardware including hinges, latches, and handles
• String line and stakes for layout
• Wood stain or sealant if not using pre-treated lumber