Privacy Fence Calculator
Calculate pickets, posts, rails, and concrete for a wooden privacy fence. Enter values for instant results with step-by-step formulas.
Reviewed by Abdullah, Technical Content Specialist
Formula
Pickets = Fence Length / (Picket Width + Gap) | Posts = (Length / Spacing) + 1 | Rails = Sections x Rails Per Section
Total pickets are calculated by dividing the fence length by the combined width of one picket plus any gap. Posts are calculated by dividing the fence length by the post spacing and adding one for the end post. Rails equal the number of fence sections multiplied by the number of rails per section.
Worked Examples
Example 1: Standard Backyard Privacy Fence
Problem:Calculate materials for a 150-foot privacy fence that is 6 feet tall with 5.5-inch pickets, no gaps, 8-foot post spacing, and 3 rails per section.
Solution:Pickets: 150 ft / (5.5/12 ft) = 328 pickets\nPosts: (150 / 8) + 1 = 20 posts\nSections: 20 - 1 = 19 sections\nRails: 19 sections x 3 = 57 rails\nConcrete: 20 posts x 2 bags = 40 bags
Result:328 pickets, 20 posts, 57 rails, 40 bags of concrete
Example 2: Small Side Yard Fence
Problem:Calculate materials for a 40-foot fence, 6 feet tall, 5.5-inch pickets, 6-foot post spacing, 2 rails per section.
Solution:Pickets: 40 ft / (5.5/12 ft) = 88 pickets\nPosts: (40 / 6) + 1 = 8 posts\nSections: 8 - 1 = 7 sections\nRails: 7 x 2 = 14 rails\nConcrete: 8 posts x 2 bags = 16 bags
Result:88 pickets, 8 posts, 14 rails, 16 bags of concrete
Frequently Asked Questions
What is the standard spacing for fence posts?
Standard fence post spacing for a privacy fence is 8 feet on center, meaning the distance from the center of one post to the center of the next post is 8 feet. Some builders prefer 6-foot spacing for added strength, especially in high-wind areas or when using taller fences. Posts should be set at least one-third of their total length into the ground, so a 6-foot fence typically uses 8-foot posts buried 2 feet deep. Corner posts and gate posts may need to be spaced differently to accommodate hardware and ensure proper structural support for the added weight and stress.
How deep should fence posts be set?
Fence posts should be set at a depth equal to one-third of the total post length, plus an additional 6 inches for a gravel base. For a standard 6-foot privacy fence using 8-foot posts, this means a hole that is approximately 30 inches deep. In areas with frost, posts should extend below the frost line to prevent heaving, which can range from 24 to 48 inches depending on your climate zone. The hole diameter should be three times the post width, so a 4x4 post needs a 12-inch diameter hole. Setting posts in concrete provides the strongest installation and prevents leaning over time.
How much concrete do I need per fence post?
Most fence posts require one to two bags of 50-pound fast-setting concrete mix per post. A standard 4x4 post in a 10-inch diameter hole that is 30 inches deep needs approximately 1.5 bags of concrete. Larger 6x6 posts or deeper holes may require 2 to 3 bags each. For best results, pour the dry concrete mix directly into the hole around the post, then add water and allow it to set. This method is faster than pre-mixing and produces reliable results. Always check that your post is plumb and properly aligned before the concrete begins to harden, which usually takes about 20 to 40 minutes.
How many rails do I need for a privacy fence?
A standard privacy fence uses either two or three horizontal rails per section. Two rails are the minimum, placed about 8 inches from the top and bottom of the fence. Three rails add significantly more strength and prevent pickets from warping or bowing, which is especially important for fences taller than 5 feet. Each rail spans from one post to the next, so the number of rails equals the number of sections multiplied by rails per section. For 100 feet of fence with 8-foot spacing, you have about 13 sections, requiring 26 rails for two-rail construction or 39 rails for three-rail construction.
References
Reviewed by Abdullah, Technical Content Specialist · Editorial policy