Fence Calculator
A fence calculator works out the materials for a fence run from its total length: the number of posts (spaced about every 8 feet), the rails between them, and the pickets to fill the spans. It also estimates the concrete for setting posts. Enter your fence length and post spacing below to get the full materials list.
Enter the fence length to see the materials.
How Do You Calculate Fence Materials?
To calculate fence materials, divide the total fence length by the post spacing (usually 8 feet) and add one for the number of posts. Each section between posts needs 2 or 3 rails, and the pickets are the run length divided by the picket width. A 120 foot fence at 8 foot spacing needs 16 posts, about 30 to 45 rails, and the pickets to fill 120 feet. The calculator also sizes the concrete for the post holes.
How Far Apart Should Fence Posts Be?
Fence posts are typically spaced 6 to 8 feet apart on center, with 8 feet being the common maximum for wood fences. Closer spacing makes a stronger fence and is used for heavy or tall panels and in windy areas. The spacing sets the post count directly, so the calculator lets you choose it: more posts mean a sturdier fence but more material and labor.
How Much Concrete for Fence Posts?
Each fence post is usually set in concrete, with a hole about 3 times the post width and one third of the post height deep. A typical 4x4 post hole takes 1 to 2 bags of concrete. For 16 posts, plan on roughly 16 to 32 bags. The calculator estimates the concrete per hole and the total, and you can refine it with the concrete bag calculator for exact hole dimensions.
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Frequently asked questions
- How many fence posts do I need?
- Divide the fence length by the post spacing (usually 8 feet) and add one. A 120 foot fence at 8 foot spacing needs 16 posts.
- How far apart should fence posts be?
- Typically 6 to 8 feet on center, with 8 feet the common maximum for wood fences. Closer spacing makes a stronger fence.
- How much concrete per fence post?
- A typical 4x4 post hole takes 1 to 2 bags of concrete. A 16 post fence needs roughly 16 to 32 bags depending on hole size.