Fence Calculator
Work out the posts and sections for a straight fence from its length and the spacing between posts.
Worked example
A straight fence 20 m long with posts no more than 2 m apart has 20 ÷ 2 = 10 sections, and needs 11 posts. If the fence were 21 m long, 21 ÷ 2 = 10.5 sections, so you would need 11 sections and 12 posts.
How we calculated this
This assumes one straight, unbroken run of fence with a post at each end. Dividing the length by the spacing gives the number of sections. A part section still needs a post at its end, so the number of sections is rounded up to a whole number, and the number of posts is one more than the number of sections.
When the length does not divide evenly, one section is shorter than the spacing. If each section is a single panel, the number of panels is the same as the number of sections. Corners, gates and branches are not included, and this does not give structural advice, footing depths, costs or guidance on boundaries or planning rules.
A result written as a plain number is exact. A result starting with “≈” has been rounded to 10 significant figures, because its exact decimal never ends or is too long to read comfortably. When an exact value is long, its full digits are shown underneath. The calculation itself is never rounded: only the display is.
What this result means
The result is the number of posts needed for one straight run of fence, and the sections between them.
Common mistakes
- Counting one post for each section. A straight fence needs one more post than it has sections.