Measure the fence run
Measure each straight run separately. Changes of direction, gates and end posts affect post counts, so a single perimeter number can hide important details.
Panels, pickets and bays
For fixed-width panels, divide usable fence length by panel width and round up. For picket systems, account for both picket width and gap. The final bay may need trimming rather than another full-width panel.
Posts and corners
A straight run of n panels normally needs n + 1 posts, but corners, gates, changes in level and shared junctions can alter the total. Count these features explicitly.
Rails and fixings
Rail quantity depends on the number of bays and rails per bay. Long runs should be converted to the stock lengths actually available so offcuts and joints are visible in the order.
Concrete for posts
Post concrete depends on hole diameter or width, hole depth and post displacement. Ground conditions and wind exposure can change the required foundation, so quantity estimation must not be treated as a structural design decision.
Waste and regional differences
BuildCalc supports the United Kingdom, United States, Canada, Australia, New Zealand, Ireland and South Africa. The geometry is universal, but terminology, units, pack sizes and common product dimensions differ. Use the dimensions printed on the product you intend to buy rather than assuming a regional default is exact.
Allow for damaged boards, end cuts and replacement pieces. Verify locally appropriate post depth and construction requirements for the fence type and exposure.
Use the related calculators
Use the calculator for your measurements, then return to this guide to check assumptions, allowances and ordering considerations.
Fence posts & panelsFence railsPost-hole concrete