Calculators/ Framing & Exterior/Fence Calculator
Fence Calculator
Posts, rails, pickets and concrete for a fence run.
Fence Calculator
ft
ft
in
in
Fence material is driven by post spacing. Eight foot centres use fewer posts but need stiffer rails, and any run that is not an exact multiple of the spacing ends in a short section you have to design for.
How this is calculated
- Sections = run length ÷ post spacing, rounded up. Posts are always one more than sections, because the run needs a post at each end.
- Pickets = run length ÷ (picket width + gap). A shadowbox or spaced picket fence uses far fewer than a solid privacy fence.
- Post holes are sized at 10 inches diameter and set a third of the post height below grade, with a two foot minimum. Check your local frost depth.
Frequently asked questions
How deep should fence posts be set?
A third of the above-ground height is the working rule, with a two foot minimum, and always below the local frost line. A six foot fence wants posts at least two feet deep.
How far apart should fence posts be?
Eight feet on centre is standard for wood fences. Drop to six feet in windy areas or for heavy privacy panels that act like a sail.
How much concrete per fence post?
About 1.1 cubic feet for a 10 inch hole two feet deep, which is two 80 lb bags. Deeper holes for taller fences need proportionally more.