Fence Calculator
Calculate the posts, rails, pickets, and concrete bags needed for building a wooden privacy or picket fence.
Calculation Results
Number of vertical fence posts required.
Number of 2x4 horizontal rails connecting posts.
Total individual vertical pickets needed.
Bags of concrete mix to secure posts (estimated at 2 bags per hole).
How This Calculator Works
To calculate fence construction materials:
- Enter the total perimeter length of your planned fence line.
- Select the distance between posts (standard is 8 feet; 6 feet provides extra wind resistance).
- Select the horizontal rail count (2 rails for fences up to 4ft tall, 3 rails for standard 6ft privacy fences, 4 rails for 8ft tall fences).
- Select the width of your fence pickets (1x6 pickets, which are 5.5 inches wide, are the standard privacy fence option).
- Enter the spacing between pickets (0 for a solid privacy fence; 2-3 inches for a decorative picket fence).
Formula & Calculations
Post and rail requirements are calculated by segmenting the fence length:
Posts = ceil(Fence Length / Post Spacing) + 1
Horizontal rails connect each post section. For example, 10 sections with 3 rails per section requires 30 rails:
Rails = Sections × Rails per Section × (1 + Waste / 100)
Picket count is based on fence length divided by the effective picket width (picket face plus spacing gap):
Pickets = ceil(Fence Length / (Picket Width + Picket Gap)) × (1 + Waste / 100)
Post hole concrete is estimated at 2 bags of 80lb concrete per post hole to ensure strong wind loading resistance.
Step-by-Step Calculation Examples
Backyard Privacy Fence (100ft fence line)
Calculating materials for a standard 6-foot solid privacy fence with 8-foot post spacing and 3 horizontal rails.
- length: 100
- post_spacing: 8
- rails_count: 3
- picket_width: 5.5
- picket_gap: 0
- waste: 5
- posts: 14
- rails: 41
- pickets: 230
- concrete_bags: 28
Frequently Asked Questions
How deep should fence posts be set in the ground?
Generally, fence posts should be buried one-third to one-half of their above-ground height. For a standard 6-foot fence, the posts should be buried 2 to 3 feet deep in concrete.
Which wood is best for fence pickets?
Western Red Cedar and Pressure-Treated Pine are the most popular choices. Cedar is naturally resistant to insects and rot and resists warping, while pressure-treated pine is highly durable and economical.