Fence Calculator

Divide the fence length by your post spacing and round up to get the number of spans. For a straight, open run, add one post for the far end. For a closed loop around a property, the span count is the post count, since the loop closes back on itself. Each gate adds two extra posts for the gate hardware.

An open run is a stretch of fence with two free ends, like a side yard between two existing walls. A closed loop wraps a full property perimeter and meets itself, so the last span shares the first post. The calculator drops one post for closed loops, which is why the count is one lower than an equivalent open run.

Take the fence length minus 4 ft per gate, convert to inches, and divide by the picket pitch (picket width plus gap), then round up. For a 200 ft fence with 5.5 in pickets and a 0.25 in gap, that is 2400 in divided by 5.75 in, or 418 pickets.

Two rails is the standard for 4 ft and 6 ft fences. Step up to three rails for 8 ft fences or any fence that has to resist heavy wind, lean from livestock, or a stack of taller pickets. Three rails also stiffens the panel and reduces the chance of warping over time.

One 50 lb bag per post is the standard residential rule of thumb for a roughly 8 to 10 in diameter hole, set about a third of the post depth into the ground. Tall fences, sandy soil, and gate posts often want two bags per post, so plan extra for high-load locations.