Barbed Wire Fence Calculator

How it works

wire = perimeter × strands × (1 + extra) · rolls = ⌈wire ÷ roll length⌉ · line posts ≈ ⌈perimeter ÷ spacing⌉ − corners − gates · corner/gate posts = corners + 2 per gate · H-braces = 2 per corner + 2 per gate · staples = 1 per strand per post

For a closed perimeter, every strand runs the full length, so the wire needed is the perimeter times the number of strands plus a few percent for sag, wrapping round strainer posts and splices. Posts sit every 2.5–4 m (8–13 ft); wider spacings of 5–6 m need wire stays between posts. Corners and gates take heavier strainer posts with H-brace assemblies in each direction of pull, because barbed wire is tensioned to about 1 kN (250 lb) per strand. Four strands are typical for cattle, five or more for smaller stock. Rolls are 1,320 ft (80 rods) in the US and usually 200–500 m in Latin America.

Worked example

A 400 m perimeter with 4 strands and 5% extra: wire = 400 × 4 × 1.05 = 1,680 m, so 1,680 ÷ 400 = 4.2 → 5 rolls of 400 m. Posts at 3 m: ⌈400 ÷ 3⌉ = 134 positions − 4 corners − 1 gate = 129 line posts, plus 6 corner and gate posts, 10 H-braces and (129 + 6) × 4 = 540 staples.

Sources: USDA NRCS Conservation Practice Standard 382 — Fence · University of Missouri Extension — Building fences for livestock

Frequently asked questions