Calculate exactly how many posts, rails, pickets, and concrete bags you need for your fence project
As an Amazon Associate, we earn from qualifying purchases. This helps support WorkshopCalc at no additional cost to you.
The number of fence boards per foot depends on the board width and fence style. For a privacy fence with 5.5-inch pickets, you need about 2.2 pickets per linear foot. For 3.5-inch pickets, you need approximately 3.4 per foot. Semi-privacy and shadowbox styles use fewer boards due to gaps between pickets. Our calculator automatically accounts for your chosen picket width and style to give you an accurate count.
Fence posts should be set at a depth of 1/3 to 1/2 of the above-ground height. For a 6-foot fence, posts should be buried 2-3 feet deep. In areas with frost, the post should extend below the frost line to prevent heaving. Always use concrete to secure posts - typically 1-2 bags of 50-pound fast-setting concrete per post. The hole should be about 3 times the width of the post (10-12 inches for a 4x4 post).
Standard fence post spacing is 6 to 8 feet on center. 8-foot spacing is most common for residential fences because it matches standard lumber lengths, minimizing waste. Use 6-foot spacing for taller fences (8 feet), areas with high winds, or when using thinner rails to prevent sagging. Corner and gate posts should always be set regardless of spacing calculations.
Most fences require 2-3 horizontal rails between posts. A 4-foot fence typically needs 2 rails (top and bottom), while 6-foot and 8-foot fences require 3 rails (top, middle, and bottom) for proper support. Rails are usually 2x4 lumber and should be positioned about 6-8 inches from the top and bottom of the fence, with the middle rail centered. For 8-foot post spacing, you will need one rail per section.
Privacy fencing has pickets installed edge-to-edge with no gaps, completely blocking visibility through the fence. Semi-privacy fencing has small gaps (typically 1-2 inches) between pickets, allowing some light and air flow while still providing partial privacy. Shadowbox fencing alternates pickets on opposite sides of the rails, creating a "good neighbor" fence that looks the same from both sides. Picket fencing has equal-width gaps and is typically shorter (3-4 feet) for decorative purposes.
Fence material costs range from $8-15 per linear foot for pressure-treated wood, $15-25 for cedar, and $25-45 for composite materials. These costs include posts, rails, pickets, and concrete. Labor typically adds $10-25 per linear foot if hiring a contractor. A 150-foot privacy fence typically costs $2,500-$4,000 for materials only with pressure-treated lumber, or $4,500-$7,500 for cedar. Our calculator provides a cost estimate based on your specific dimensions and material selection.