Fence Calculator
Calculate fence posts, rails, and pickets from perimeter, height, and post spacing.
Returns lumber counts and concrete bags needed for wood privacy fences.
Estimating fence materials requires calculating the perimeter accurately, then determining how many posts, rails, and pickets are needed based on your chosen style and post spacing.
Key formulas:
Number of Posts = (Total Perimeter ÷ Post Spacing) + 1 (for each straight run) Number of Panels = Total Perimeter ÷ Panel Width Number of Pickets per Section = Section Width ÷ (Picket Width + Gap Width) Total Pickets = Pickets per Section × Number of Sections Number of Rails = Number of Sections × Rails per Section (typically 2 for under 4 ft, 3 for 6 ft fences)
What each variable means:
- Post Spacing — usually 8 feet on center for wood, 6 feet for vinyl or chain link.
- Panel Width — pre-built panels are typically 6 or 8 feet wide.
- Picket Width — standard dog-ear pickets are 3.5 inches wide; nominal 4-inch.
- Gap Width — privacy fences: 0–0.25 inches; semi-privacy: 0.5–1.5 inches.
Common material quantities per 100 linear feet (6-ft privacy fence, 8-ft post spacing):
- Posts (8 ft long for 6 ft above grade): 14 posts
- Rails (2×4, 8 ft): 36–42 rails (3 rails per section)
- Pickets (1×6, 6 ft): ~280 pickets
- Post concrete: 2 bags (60 lb) per post
Worked example: Backyard perimeter: 120 feet. 6-foot privacy wood fence, posts every 8 feet.
Posts = (120 ÷ 8) + 1 = 16 posts Sections = 120 ÷ 8 = 15 sections Rails = 15 × 3 = 45 rails Pickets = (96 in ÷ 3.75 in) × 15 = 25.6 × 15 ≈ 384 pickets (add 10% waste = 422 pickets)
Cost benchmark: Material cost for a 6-ft wood privacy fence runs $15–$30 per linear foot; vinyl runs $20–$40 per linear foot; chain link $10–$20 per linear foot.