Fence Calculator

Plan a wood privacy or picket fence: how many posts, rails and pickets you'll need for a given run.

How the Math Works

The Fence Calculator uses a straightforward mathematical formula to determine the exact number of components needed for your wood fence project: posts = length ÷ spacing + 1. This formula works by first dividing the total fence length by the desired spacing between posts, which gives you the number of intervals. You then add one to get the total number of posts needed, since each interval requires a post at both ends. For example, a 20-foot fence with 8-foot post spacing would require 20 ÷ 8 + 1 = 3.5, rounded up to 4 posts.

Practical Applications

To use this calculator practically, start by measuring the total length of your fence in feet. Decide on your preferred post spacing, which typically ranges from 6 to 10 feet depending on fence style and local building codes. Enter these two measurements into the calculator to instantly receive your post count. Once you have your post total, multiply by the number of rails per section (usually 2-3) to determine lumber requirements, and calculate pickets by measuring the fence length and determining how many pickets fit within that space based on their width.

Day-to-Day Use

This calculator saves you significant time and money on DIY fencing projects by preventing costly mistakes and material waste. Instead of guessing how many boards to purchase at the lumberyard, you can confidently buy exactly what you need, avoiding both shortages that delay your project and excess that creates unnecessary expenses. Whether you're building a privacy fence to separate your property from a neighbor, enclosing a garden to protect plants from animals, or creating a boundary for safety, accurate measurements ensure professional results without the frustration of running out of materials mid-project.

Worked example

100 ft fence, 8 ft spacing, 3 rails, 5.5 in pickets touching → 14 posts, ~219 pickets, 300 ft of rail.

FAQ