Fence Calculator

How to Calculate Fence Materials

Our fence calculator helps you estimate posts, rails, pickets, and concrete for your wood fence project. Whether building a privacy fence, picket fence, or board-on-board style, accurate material calculations save time and money.

Fence Post Spacing

• 6 ft spacing: For tall fences (8 ft), windy areas, or heavy gates
• 8 ft spacing: Standard for most residential fences
• 10 ft spacing: For lightweight or decorative fences only

Rail Requirements

Fences under 5 ft typically use 2 horizontal rails. Fences 6 ft and taller should use 3 rails for stability. Rails can be 2x4s (lighter fences) or 2x6s (heavier pickets or windy areas).

Post Depth and Concrete

Fence posts should be buried at least 1/3 of their total length, with a minimum of 2 ft in the ground. Each post hole should be 3x the post width (12 inches for 4x4 posts) and filled with concrete for maximum stability.

Common Fence Styles

• Privacy fence: No gaps between pickets
• Board-on-board: Overlapping boards for privacy from both sides
• Shadowbox: Alternating boards on each side of rails
• Picket fence: 2-3 inch gaps between pickets

The Fence Material Formula

This calculator estimates a wood fence with the following steps:

1. Posts: fence length divided by post spacing, rounded up, plus 1 for the end of the run
2. Rails: number of sections (posts minus 1) times rails per section — 2 rails for fences under 6 ft, 3 rails for 6 ft and taller
3. Pickets: fence length in inches divided by (picket width + gap), plus 5% waste, rounded up
4. Concrete: 2 50-lb bags per post, plus 2 extra bags per gate for the gate posts

Worked Example: 100 ft Privacy Fence

A 100 ft long, 6 ft tall privacy fence with 8 ft post spacing, 5.5" pickets, no gap, and 1 gate:

• Posts: 100 / 8 = 12.5, rounds to 13 sections, plus 1 = 14 posts
• Rails: 13 sections x 3 rails = 39 rails
• Pickets: 1,200 inches / 5.5" = 218, plus 5% waste = 230 pickets
• Concrete: 14 posts x 2 bags + 2 extra for the gate = 30 bags

At the 2026 installed range of $15-$60 per linear foot, 100 ft of fence runs roughly $1,500 to $6,000 depending on material, region, and site conditions.

Fence Cost Factors and Common Mistakes

Material drives most of the budget: chain link is the cheapest, pressure-treated wood sits in the middle, and vinyl or composite cost the most per foot. Height, slopes and rocky soil, the number of gates, and old fence removal all move the price. Cost also varies by region, and many areas require a permit.

• Waste factor: 5% on pickets covers warped or split boards; buy a few extra pickets for future repairs
• Common mistakes: building on the wrong side of the property line, skipping the 811 utility locate call, and setting posts too shallow for the local frost line
• Gate planning: gate posts carry extra load — set them deeper and use more concrete than line posts
• Wind: solid privacy fences catch wind like a sail; use 6 ft post spacing in exposed areas