The measurement that decides how a fence line behaves
Most buyers start a perimeter project by choosing the mesh or the panel. In practice the figure that decides how long the line stays tight, how it behaves in the first strong wind and where the total material cost lands is a different one: concrete post spacing. Set the posts close together and you get a strong but expensive line; open them up and you save on material while buying a fence that sags within a couple of seasons. The right figure sits between the two, and the land itself largely dictates it.
The two mistakes we see most often are opposites of each other. One buyer stretches the posts out to four or five metres to shorten the material list; the mesh bellies out between supports and the line drops under the first snow load. The other orders far more posts than needed but sets them in shallow foundations, wasting both money and labour, because what holds a post upright is its footing rather than the number of posts on the line. Spacing has to be decided together with post height, wire gauge and ground conditions.
This guide answers one question with real measurements: how far apart should the posts go, which variables pull that figure up or down, and how does the spacing you choose change your order list?
How wide should concrete post spacing be
The working band is 2.5 to 3 metres. Neither figure is arbitrary. The upper limit of 3 metres is the widest span over which a tensioned line wire carries its own weight on flat, sheltered ground without visible sag. The lower limit of 2.5 metres is the safe figure for exposed, sloping or livestock-pressured lines. Half a metre sounds like a detail; over a 100 metre run it is five posts.
Four questions settle the figure. Is the site exposed to wind, how high is the fence, what is the wire gauge, and will anything extra such as barbed wire sit on top of the line? A 3 metre span that causes no trouble in a sheltered garden will show itself in the first winter on an open field with exactly the same mesh. Concrete post spacing lands at the lower or upper end of the band according to those four answers; there is no default figure in the middle that applies to everyone.
Post length matters too. A 200 cm concrete fence post leaves roughly 150-160 cm of working height above ground and suits garden boundaries, field lines and grazing areas. A 240 cm concrete fence post gives about 180-200 cm of working height once the buried section is deducted, which is why it is the length most often requested for factories, warehouses, schools and housing estates. The taller the line, the longer the lever the wind works on, so on high runs it is better to pull concrete post spacing down to 2.5 metres than to hold it at the top of the band.
Concrete post spacing and wire sag: how the two are linked
A tensioned wire does not run as a straight line between two posts; it forms a shallow curve. The wider the span, the deeper that curve becomes, and past a certain point it is visible from a distance. There are three ways to reduce sag: narrow the span, add another line of straining wire, or move up a wire gauge. All three cost money, but the first is usually the cheapest — adding one post to a run is less expensive than taking the whole line up a gauge.
In our wire mesh and posts group, galvanized chain link fence is stocked in wire gauges from 2.0 mm to 3.0 mm, with 5x5 cm and 6x6 cm mesh apertures, 150 cm high, in 20 metre rolls. Thin wire and wide spans do not go together: with 2.0 mm wire keep concrete post spacing at 2.5 metres, and only open up towards 3 metres once you are at 2.5 mm or above. On chain link fence the relationship matters more than it does on panel runs, because a panel frame carries part of the load itself, while on mesh the entire load transfers to the straining wire and then to the post.
How ground, slope and wind change the figure
Same fence, same mesh, same height — but change the ground and the span changes with it. In loose, sandy or high water table ground a post works in its own socket, and narrowing the span alone will not fix that; the footing has to go deeper as well. In firm clay the standard practice runs without trouble. Rocky ground often reverses the logic: digging is laborious, so instead of adding posts it makes more sense to build fewer, deeper, genuinely solid points and hold the span.
On sloping land a fence steps down in sections, and a post must land at every break point, so the slope sets the layout for you. Following a rigid "one post every three metres" rule on such a run is a mistake. Divide the line by its break points first, then share the remaining straight sections into equal spans. On sloping ground it is always cheaper to add a couple of posts to the list than to come up short on site.
Wind is the load people think about least and the one that does the most damage. On open fields, ridge lines and corridors between buildings the wind hits the fence face on and transfers the load straight into the posts. On those runs, pulling concrete post spacing back to 2.5 metres is more effective than moving up a wire gauge, because the failure mode is not the wire breaking but the post leaning over time. Where barbed wire or razor coil is added on top, the effect grows further, since that extra load sits at the very top of the post body.
On panel fence the product sets the span
With mesh you choose the span; with panels the panel chooses it. Our stocked panel fence is produced 250 cm wide, in 50, 75, 100, 120, 150, 180 and 200 cm heights, with 4 mm and 5 mm wire, a 50x200 mm aperture, in RAL 6005 green over a galvanized and powder coated finish. Because the panel is 250 cm, posts are set centre to centre to match it, which means the spacing question is already answered by the product on a panel fence line.
That changes the order list as well. On a panel run the post count matches the panel count, plus a few extra for corners and terminations. On a mesh run you divide the metrage by the span you selected. If you are comparing the two systems for the same plot, this is exactly where the material lists diverge: the panel fixes the figure, while on mesh concrete post spacing stays your decision. The same logic holds when steel tube posts are used instead of concrete ones; only the section and the fixing method change.
Foundation depth and struts: the invisible half of the span
However well the span is chosen, the line will not hold if the footing is shallow. Foundation depth follows the ground: in normal soil 40-50 cm is accepted for a 200 cm post, rising to roughly 50-60 cm for a 240 cm post. Both figures increase in loose or sandy ground, where a concreted footing becomes necessary. As the post gets taller the wind lever grows, the overturning moment grows and the footing goes deeper; the three work together.
Struts at corners and beside gates are not optional. When the wire is tensioned, the horizontal force peaks at the corner post, and without a strut that corner will lean inwards over time regardless of the span used elsewhere. In the same way, the wire must not be tensioned before the concrete has set. That is the most common and most expensive piece of haste on site: posts go in, the wire is pulled the same day, and a fortnight later a slow inward lean starts along the whole run.
When planning the work, rather than opening every hole at once it gives a cleaner result to set the corner and gate posts first, wait for the concrete, then place the intermediate posts against a tensioned string line. Setting them to the string also removes the gap between the concrete post spacing on paper and the figure that actually ends up on the ground. This is work a buyer can run with their own crew; getting the setting out right matters far more than speed.
How many posts: working a 100 metre run
The arithmetic is simple: divide the total perimeter by the span you chose, then add an allowance for corners and gates. A 100 metre perimeter at 3 metre spacing gives roughly 34 posts; ordering 37-38 including corners and struts prevents running short. Build the same line at 2.5 metres and the count passes 40. The difference is a price paid for the conditions the line has to work in — unnecessary in a sheltered garden, unavoidable on an open field.
If you do not know your perimeter, work it from the shape rather than the area. A 1000 square metre plot in a square shape has sides of about 31.6 metres and a perimeter near 126 metres. The same 1000 square metres as a long 20 by 50 metre strip runs to 140 metres. Take the metrage from real side dimensions, never from the area alone: identical plots can differ by more than ten metres of perimeter, and that difference lands directly on the post count.
Straining wire, tying wire, corner struts and gate openings belong on the same list. Gate widths come off the run, and the posts either side of a gate are treated as corner posts rather than intermediates. Working your concrete post spacing over the straight sections that remain after corners and gates are deducted is the most practical way to get the list right the first time.
Turning the calculation into an order
Once the material is chosen, three things remain: quantity, delivery and timing. Quantity is covered above. Freight is never included in the goods price; it is quoted separately after the order according to destination, quantity and the delivery term agreed, and export orders are quoted EXW Ankara or FOB Turkish port. Lead time depends on the quantity and on whether the posts, mesh and fittings ship together.
Current dimensions, height options and stock status are shown on the product pages. As a supplier and exporter shipping from our Ostim stock in Türkiye, we do not publish fixed figures in guides like this one, because steel-linked pricing moves and an out of date number helps nobody. Send your metrage and the concrete post spacing you have chosen and we will list posts, mesh, straining wire and fittings together, then issue a net quote within one business day — you can reach us through the contact page. On welded wire mesh, chain link fence and panel fence runs alike, the list starts with the same figure: how far apart the posts go.
