Line versus corner, and why the cost is not per foot
Pricing a fence by the foot hides where the money goes. A straight run of woven wire on wood line posts at 16 foot centres is a modest cost per foot and goes up fast once you have a rhythm. A braced corner is two heavy posts set deep, a horizontal rail between them and a diagonal tension wire twisted tight, and it takes a fraction of an hour by itself. Four corners and two gates on a small square pasture means six brace assemblies, twelve heavy posts and twelve holes that are deeper and wider than the line holes. On a short perimeter that is most of the work.
The calculator counts a brace at every corner, every dead end and both sides of every gate, because those are the places tension terminates. A corner that turns without a brace pulls itself inward over a season or two, and once it starts leaning the whole run slackens. There is no way to retension a fence off a leaning corner.
What each fence type is counted as
| Type | Sold as | How the count works |
|---|---|---|
| Woven wire field fence | Rolls, commonly 100 or 330 ft | One roll height covers the whole fence, so rolls equal length divided by roll length |
| Barbed wire | Spools, often 1,320 ft | Length times number of strands, then divided by spool length |
| High-tensile smooth | Reels, often several thousand ft | Same strand arithmetic, but posts sit much further apart |
| Electric polywire or tape | Reels, varying | Strand arithmetic; the energizer and grounding are a separate job |
| Welded panels | Individual panels, commonly 16 ft | Panels rounded up, one post at every joint plus one |
Roll and spool lengths are entered rather than assumed because they vary by manufacturer and by the gauge and height you buy. Check the tag on the roll you are actually pricing; a fence figured at 330 ft rolls and bought as 100 ft rolls is a different number of joints as well as a different price.
Spacing, height and what the animal does
Post spacing here defaults to 16 ft, which suits woven wire and barbed wire on most terrain. High-tensile systems are built the other way around, with widely spaced posts carrying high wire tension and light droppers between them to keep the wires apart, and running them at woven-wire spacing works but wastes most of what the system is for. Rolling ground changes both: a wire fence follows the ground, and every dip needs a post at the low point held down or the wire lifts.
The animal decides height and spacing, and it is not the animal you have today. Sheep and goats test the bottom of a fence, cattle lean on the middle of it, horses run into it and get injured by wire that a cow would ignore, and pigs go under anything. What the fence is asked to keep out matters as much: a fence that holds calves is not a fence that discourages coyotes. Your county extension service publishes fencing material for local conditions and the local predator picture, and that is the right source for the specification rather than any general table.
Electric fence, briefly and honestly
Polywire and tape are counted here as strands like any other wire, because that is all a quantity calculator can responsibly do with them. An energizer delivers a genuine shock hazard, and a line shorting to dry vegetation is a real ignition risk in a dry season. Grounding is the part people get wrong and it is the part that determines whether the fence works at all. Read the manufacturer instructions for the specific energizer, and get someone who has installed one to look at the ground field before you rely on it.
Before you set the first post
Boundary fences are a legal matter as well as a construction one. State fence law differs substantially — on who pays for a shared boundary fence, on what construction counts as a lawful fence, on whether an owner is liable for stock that get out, and on setback from a road or a property line. Some of it is state statute and some is county. None of it is something to take from a web page. The county extension office and, for anything on a boundary, a conversation with the neighbour in advance, will save more than the fence costs.
For post holes and the concrete that goes in them, the fence post calculator works the hole side of the same job. If the fence is dividing pasture rather than enclosing it, the pasture stocking and rotation calculator is what decides how many divisions you want in the first place, and the chicken coop size calculator covers a run at the small end of the same problem.
Questions people ask
How many rolls of woven wire for a quarter mile?
A quarter mile is 1,320 feet. At 330 ft per roll that is four rolls with nothing spare, and at 100 ft per roll it is fourteen. Roll length varies by manufacturer, height and gauge, which is why the calculator asks rather than assuming, and the number of joints matters as much as the number of rolls: every roll end is a splice that has to be tensioned and tied. Take the gate openings out first, because a 1,320 ft perimeter with two 12 ft gates is 1,296 ft of fence and that can be the difference between four rolls and five once you allow for splice overlap.
What is an H-brace and do I really need one at every corner?
An H-brace is two heavy posts set deep, a horizontal rail between them at the top and a diagonal wire from the top of one to the bottom of the other, twisted tight so the assembly resists being pulled over. It exists because wire under tension pulls its terminating post toward the run, and a single post in the ground has almost no resistance to that. You need one wherever tension terminates or turns: corners, dead ends and both gate posts. You do not need one at line posts, which only carry the wire vertically. A fence built without braced corners will look fine the day it goes up and will be visibly leaning inside a couple of seasons, and there is no way to retension it afterwards without rebuilding the corner.
How far apart should livestock fence posts be?
Twelve to sixteen feet is the common range for woven wire and barbed wire on reasonably level ground, closer on rolling terrain, and considerably wider for high-tensile systems that rely on wire tension with light droppers between posts. The specification depends on the animal, the wire, the terrain and how much pressure the fence takes, so it is an input here rather than a fixed value. Ground that dips needs a post at the low point anchored down, or the wire lifts and something goes under it. Your county extension service publishes fencing guidance for local soils and conditions and is a better source for a specification than any general figure.
Should I include the gate openings in the perimeter?
Measure the full perimeter, then let the calculator subtract the gate widths, which is what it does. That order matters because the gate posts are braced posts and get counted separately from the line posts, and because a gate opening removes fence line but adds two of the most expensive posts in the job. Make the openings wider than you think you need. A 12 ft gate is comfortable for animals and tight for a tractor with an implement on the back, and the cost difference between a 12 ft and a 16 ft gate is far smaller than the cost of taking a section of fence down every time you need to get equipment in.
Is electric fence cheaper than woven wire?
Per foot of material, usually yes by a wide margin, which is why temporary and rotational grazing divisions are so often polywire. The comparison is not only material cost though. Electric fencing is a psychological barrier that works because animals have learned it, so it needs the animals trained to it, it needs the energizer maintained and the line kept clear of vegetation, and it fails as a barrier the moment power is lost. Grounding is the part that determines whether it works at all and the part most often done inadequately. Energizers are also a genuine shock hazard and a fire risk where a line shorts to dry vegetation. Follow the manufacturer instructions for the energizer and get someone experienced to check the installation rather than working it out from general guidance.