Standard Wood Fence Post Sizes

Common Sizes

• Common fence post dimensions are in multiples of two -- 4, 6 or 8 inches. A 4-by-4-inch post will support most home fences and is a size commonly used for yard fences with wood covering. Most such posts are square, but a few are rectangles, like 4 by 6 inches. Some styles of wood yard fences, like stockades, use round posts, generally 4 inches in diameter.

Taller Fences

• Taller fences or those in areas subject to very high winds or other forces usually use 6- or 8-inch posts, either square or round. Old railroad ties, which are roughly 8-by-8, and utility poles, which vary from 10 to 12 inches, often are used for posts in sturdy fences, either with wood slats or with some type of wire covering.

Length Varies

• The length of posts depends on the type of fence. Typically about a third of the post should be buried in the ground, preferably set in concrete to reduce danger from moisture rot and insect pests. A 6-foot privacy fence, for instance, will usually require a post at least 8 feet long, with 2 feet set in the ground.

Split Posts

• Farm or livestock fences covered with wire rather than wood frequently use split-rail posts, timbers split lengthwise and not cut into any regular size. Split posts usually are 4 to 6 inches in diameter. Larger rectangular or round posts usually are used at corners or for gate openings.