This is the simplest way to work it out. Take your total fence length, divide it by the width of each bay (the distance between posts), round it up to get the number of gaps, then add one extra post so the fence has a post at both ends. That final “+1” is where people go wrong and end up one short. When you’re ready to order, you can browse Fence Posts or the wider Fencing, Decking & Landscaping range.
Understanding Fence Post Spacing Properly
Fence posts are not just something you fix panels to. They are the structural backbone of the entire fence line. Every panel, rail, gravel board and fixing ultimately relies on the post to resist wind load, ground movement and long-term timber movement. Getting the quantity right is not just about cost — it is about structural integrity. Under-ordering means weak end bays or improvised spacing. Over-stretching spacing to “make it work” increases leverage on each post and reduces overall rigidity.
The reason the formula works is because fencing is modular. When you divide the total run by your chosen bay width, you are calculating how many structural spans you are asking each post to carry. Each span creates force transfer at both ends. That is why a fence with six bays requires seven posts. There must always be a structural termination point at both ends of the run. This is basic load distribution — not just a counting trick.
Why 1.83m Matters for 6ft Panels
A standard 6ft wide fence panel measures approximately 1.83 metres. That measurement dictates post positioning. Posts are typically set to match panel width (allowing for slot depth in concrete posts or fixing clearance on timber posts). If posts are set wider than panel width, you introduce unnecessary stress on rails and fixings. If posts are set significantly narrower, you create trimming waste and unnecessary cost.
This is why 1.83m is widely recognised as the “standard” bay width in UK domestic fencing. It aligns with manufacturing dimensions, reduces site cutting, and ensures panels sit square and supported. You can browse suitable options in our Fencing, Decking & Landscaping collection once you’ve calculated your run.
Structural Considerations Beyond Simple Maths
Post quantity is only one part of the equation. Post depth, ground conditions and post material are equally important. Timber posts require sufficient embedment depth and appropriate treatment class for ground contact. Concrete posts offer longevity and dimensional stability but require accurate alignment before backfilling. Wind exposure also plays a significant role; open rural sites will place more load on a fence than sheltered suburban gardens.
For most domestic installations, closer spacing increases rigidity and reduces deflection under wind load. Wider spacing reduces material cost but increases bending forces on rails and fixings. There is always a balance between structural performance and material efficiency. Once you know your required quantity, you can choose from timber or concrete options in our Fence Posts range.
Avoiding Common Installation Mistakes
The most frequent mistakes seen on fencing projects are simple: miscounting posts, stretching bays to compensate for shortages, and failing to account for the final post at the end of the run. Once concrete is set, corrections become expensive. Taking a few minutes to calculate accurately prevents mid-job supply runs and ensures alignment remains consistent across the entire fence line.
If you are planning a full installation, consider reviewing your panels, gravel boards, fixings and post mix at the same time so quantities align across the whole project. Everything required for a complete fence build can be found within our Fencing, Decking & Landscaping category.
Final Practical Rule
Measure carefully. Choose your bay width deliberately. Divide the run. Round up. Add one. Order correctly. Build once.
