The same paddock count can cost twice the fence
Cutting a rectangle into n pieces can be done as strips one way, strips the other way, or any grid whose rows times columns equals n. Each arrangement costs a different total length, and on a long thin field the difference is large.
Take 1,320 by 660 ft, which is 20 acres, cut into six. Six strips across the length is five lines of 1,320 ft, so 6,600 ft. Six strips across the width is five lines of 660, so 3,300. A two by three grid is one line of 1,320 plus two of 660, which is 2,640. Every one of those gives six paddocks of 3.33 acres. The cheapest costs 40 percent of the dearest.
| Layout | Long lines | Short lines | Internal fence | Paddock shape |
|---|---|---|---|---|
| 6 x 1 grid | 5 x 1,320 | none | 6,600 ft | 1,320 x 110 ft |
| 3 x 2 grid | 2 x 1,320 | 1 x 660 | 3,300 ft | 660 x 220 ft |
| 2 x 3 grid | 1 x 1,320 | 2 x 660 | 2,640 ft | 440 x 330 ft |
| 1 x 6 grid | none | 5 x 660 | 3,300 ft | 220 x 660 ft |
The rule behind the pattern: lines running the long way are expensive because each one is the full length of the field, so you want as few of those as possible. On a field twice as long as it is wide, that means splitting the width as little as the paddock count allows.
Square fields behave differently
On a square field the two directions cost the same, so the cheapest layout is the grid closest to square. Four paddocks out of a 660 by 660 field is 1,320 ft as a two by two, against 1,980 ft as four strips. Nine paddocks is a three by three at 2,640 ft, against 5,280 ft as nine strips. The saving grows with the paddock count, because strips keep adding full-length lines while the grid keeps splitting what is already there.
A lane costs fence and costs grazing, and buys every paddock a gate
The plain grid gives short internal fences but stock have to cross one paddock to reach another, which means gates in the right places and a lot of opening and closing. A lane down the middle gives every paddock its own gate onto a track, which is why almost every rotational setup ends up with one.
It is not free. A 16 ft lane down the 1,320 ft length of the field is 2,640 ft of fence for the lane alone, plus cross fences on both sides. With three paddocks a side, that is two cross lines per side at 322 ft each, so 1,288 ft, and 3,928 ft in total against 2,640 for the plain grid. It also takes 21,120 sq ft — just under half an acre, 2.4 percent of the field — permanently out of grazing. What you get is six gates onto a track instead of a puzzle.
Count the braces, not just the wire
Every internal fence line ends at the outside fence, and both of those ends need a braced assembly to pull against. Three internal lines is six end assemblies. Where a long line crosses a short one there is an internal junction, and on the two by three grid there are two of them. Those are the expensive points in any fence — a braced end assembly costs several times what an equivalent length of line costs — and they are the ones left off estimates that were made by measuring feet on a map.
Take the length from this page over to the livestock fence calculator, which turns a perimeter into line posts, corner and end posts, braced assemblies, wire rolls, staples and a gate allowance. For what the field will carry, the pasture stocking rate calculator takes your own figures for forage and animal demand. If the fence line runs over broken ground, the fence on slope calculator handles the extra length a slope adds, and the gate sag brace calculator deals with a wide gate that wants to droop.
Questions people ask
How much cross fencing do I need to make six paddocks?
It depends entirely on the shape of the field and which way the lines run. On a 1,320 by 660 ft field, 20 acres, six paddocks costs 2,640 ft as a two by three grid, 3,300 ft as six strips across the short way, and 6,600 ft as six strips the long way. All three give paddocks of 3.33 acres. The calculator checks every grid whose rows times columns makes your paddock count and reports the cheapest along with both strip options.
Is a grid always better than strips?
For fence length, on any field that is not extremely long and thin, the grid usually wins and it wins by more as the paddock count rises. But length is not the only thing that matters. Strips give every paddock the full width of the field, which makes them easy to reach from one end and easy to lay out with temporary wire. A grid puts interior paddocks behind other paddocks, and that is exactly the problem a lane solves. The numbers here are the fence cost; the layout decision includes things no calculator sees.
Is a lane worth the fence and the lost ground?
On the default field a 16 ft lane adds about 1,290 ft of fence over the plain grid and takes just under half an acre, 2.4 percent of the field, out of grazing permanently. In exchange every paddock gets its own gate onto a track and nothing has to be moved through anything else. Most people who rotate stock regularly decide that is worth it and most people rotating twice a year decide it is not. The calculator gives both totals so it is a comparison rather than a guess.
How many paddocks should I have?
Not a question for this page and not one arithmetic can answer. How many paddocks, how long stock stay in each and how long each rests depend on the forage, the species, the season, the rainfall and what you are trying to achieve, and getting it wrong damages the pasture rather than just costing money. Your cooperative extension service and a grazing adviser who has walked the ground are the right sources. Bring them a number and this page tells you what the fence costs.
Why does the calculator count end assemblies separately?
Because they are where the money is. A braced end assembly is two or three posts, a horizontal brace and a diagonal wire, and it costs several times what the same few feet of plain fence line costs. Every internal line has one at each end, so three lines is six assemblies. An estimate made by measuring feet on a map and multiplying by a price per foot misses all of them, and on a heavily subdivided field that is a large miss. The livestock fence calculator prices the assemblies once you have the count.