Fence Material & Lumber Calculator

For a straight 100-foot fence with standard 8-foot post spacing, you will need 14 posts (13 sections + 1 terminal end post). If you use 6-foot spacing for higher wind resistance, you will need 18 posts (17 sections + 1 terminal post).

According to ASTM and standard building guidelines, a fence post must be buried to a depth equal to at least 1/3 of its total height. For example, a 6-foot tall fence requires an 8-foot post, with 2 feet buried below the surface. In cold climates, posts must extend below the local frost line to prevent frost heaving.

A standard 4x4 wooden post set in a 10-inch to 12-inch diameter hole typically requires two 50-lb bags of fast-setting concrete. Taller fences (8 feet or higher) or heavy gate anchor posts generally require three 50-lb bags.

A 6-foot fence requires 3 horizontal 2x4 rails per section (top, middle, and bottom) to prevent vertical pickets from twisting or bowing under weather exposure. Fences 4 feet tall or shorter only require 2 rails.

Convert total fence length into inches and divide by the effective width of the picket (actual board width plus the intended spacing gap). For example, a 100-foot fence (1,200 inches) using standard 5.5-inch nominal pickets with zero gap requires approximately 219 pickets. Add a 10% cutting waste buffer (241 pickets total).

8 feet is the industry standard for most residential wood and vinyl privacy fences because dimensional 2x4 rails come in 8-foot lengths. 6-foot spacing is recommended in high-wind zones, coastal regions, or when installing modern horizontal fence boards to prevent mid-span sagging.