Calculate posts, rails, and pickets needed for your fence project with precision.
Updated 4/29/2026
feet
feet
inches
inches
Posts Needed
14
Pickets Needed
219
Rails (Horizontal)
39
⚠ Rails Estimate: The horizontal rails calculation assumes fixed 8-foot sections and exactly 3 rails per bay (top, middle, bottom). Actual rail requirements depend on:
Fence material calculation determines the exact quantity of posts, rails, and pickets needed to construct a complete fence. Posts are vertical supports spaced evenly along the fence line, typically buried 1/3 to 1/2 their height for stability. Rails are horizontal members connecting posts and providing structural support. Pickets are the vertical boards or balusters that fill the space between rails and create the visible fence surface.
Each component requires different calculations. Posts depend on the fence length and spacing interval. Rails depend on spans and height configuration (typically 2-3 rails per fence). Pickets depend on their width and the desired gap between them. Accurate calculation prevents material waste, reduces costs, and ensures you have everything needed before starting construction.
Picket spacing affects both the aesthetic appearance and the privacy level of your fence. Tight spacing (minimal gaps) provides maximum privacy but requires more materials. Loose spacing (larger gaps) reduces material costs and allows airflow and light penetration. Standard residential fences typically use 1-2" gaps between pickets, while privacy fences use tight spacing.
Standard Post Spacing
| Residential | 6-8 ft |
| Commercial | 6 ft |
| Livestock | 4-6 ft |
| Privacy | 4-8 ft |
Common Picket Widths
| Narrow | 3.5" |
| Standard | 5.5" |
| Wide | 7.5" |
| Extra Wide | 11.25" |
Scenario: Building a 100-foot privacy fence with 8-foot post spacing, 5.5" wide pickets, and 0.5" gaps between pickets.
Step 1: Calculate posts needed
(100 ft ÷ 8 ft) + 1 = 13.5 → 14 posts
Step 2: Calculate picket spacing
Picket + gap = 5.5" + 0.5" = 6"
Step 3: Calculate pickets needed
(100 ft × 12 in/ft) ÷ 6" = 200 pickets
Step 4: Calculate rails needed
(100 ft ÷ 8 ft) × 3 rails = 37.5 → 38 rails
Final Material List (plus 10% waste)
14 posts, 220 pickets, 42 rails
Result: This materials list ensures you have everything needed for a complete 100-foot privacy fence with appropriate spacing for privacy and structural integrity.
Posts are the structural backbone of any fence. They bear the weight of rails and pickets, resist wind loads, and prevent the fence from collapsing. Posts must be spaced closely enough (typically 6-8 feet) to maintain structural integrity while keeping costs reasonable. Closer spacing is required in high-wind areas or for very tall fences.
The rule of thumb is to bury 1/3 to 1/2 of the post's above-ground height. For a 6-foot fence, burial depth should be 2-3 feet. This depth prevents frost heave in northern climates, resists wind forces, and prevents rot. Concrete footings increase stability and longevity significantly, especially in loose or sandy soil.
Rails are horizontal members that run between posts and provide the primary structural support. Pickets are the vertical boards attached to the rails that fill the space between rails and create the visible fence surface. You typically need 2 rails for 3-4 foot fences and 3 rails for 5-6 foot fences to maintain proper spacing and strength.
Always order 10-15% more material than calculated to account for mistakes, cuts, breakage, and future repairs. This extra allowance prevents expensive last-minute trips for additional material and ensures you can match wood grain and finish for future maintenance. For larger projects, 10% is usually sufficient; for first-time builders, 15% is recommended.
Corners require additional consideration—you may need extra posts or special corner posts. Gates require standard posts as hinges points and typically have a double rail system for strength. Account for gate height and width separately, then subtract from the total picket/rail quantities. Heavy-duty hinges and latches require reinforced posts.
Yes—sloped terrain complicates calculations. You can either follow the slope (stepping the fence level in sections) or maintain a level top. Stepping requires more materials and complex cuts. Maintaining level top means variable picket heights per section. Contoured terrain may require intermediate posts closer than normal spacing. Survey uneven areas carefully before ordering materials.
Disclaimer: Fence material calculations are estimates based on standard spacing and design assumptions. Actual requirements vary by fence type, terrain, gate placement, and local conditions. This calculator provides planning estimates only. Always order 10-15% extra material for waste and mistakes. Prices vary by region, material quality, and supplier. Labor costs are separate. Verify local zoning and permit requirements before installation. Results are for budgeting purposes only.