Fence calculator
Posts, rails, pickets and concrete for a wood or steel-post fence.
Posts
0 posts
How it works
fence without gates = length - gates x gate width sections = fence without gates / post spacing, rounded up posts = sections + runs + gates pickets = fence without gates x 12 / (picket width + gap) x (1 + waste) concrete per hole = (3.1416 x (hole diameter / 2)^2 - post area) x depth
Every straight run needs a post at each end, and each gate adds one more, since it hangs between two posts of its own. Posts go 6 to 8 feet apart; 8 feet suits standard 8 foot rails. Two rails carry a 4 foot fence, three a 6 foot privacy fence and four an 8 foot one. Pickets on a privacy fence go tight together, and a picket fence leaves a gap of about one picket width.
Holes are usually about three times the post width across and a third to a half of the height above ground deep, and below the frost line where the ground freezes. Posts are cut from the next stock length up: 8 feet for a 4 or 5 foot fence, 10 feet for 6 feet and 12 feet for 8.
Questions
- How far apart should fence posts be?
- 6 to 8 feet. 8 feet matches standard rail lengths and is the usual choice for wood privacy fences; closer spacing suits windy sites and heavy gates.
- How deep should fence post holes be?
- A third to a half of the post's height above ground, so about 2 to 3 feet for a 6 foot fence, and below the frost line in cold climates.
- How many bags of concrete per post?
- About one and a half 80 lb bags for a 4 x 4 in a 10 inch hole 2 feet deep. The calculator works it out from the hole and post size.
- What should I check before digging?
- Call 811 to have buried lines marked, confirm the property line, and check the local permit and height rules and any HOA rules.
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