Fence Picket Calculator
About Fence Picket Calculation
The Fence Picket Calculator helps determine the required number of fence pickets, posts and rails for a straight fence section. It also calculates the length of one picket and one post, as well as the total length of pickets, posts and rails required for constructing fences with wooden, plastic or metal panels.
The calculation is suitable for preliminary material estimates and for comparing fence designs with different picket widths, gaps, post spacing and numbers of rail rows.
Guidelines and recommendations
Number of fence pickets
Calculation principle. The calculator places pickets of the specified width along the fence length with the selected gap between adjacent elements. Only whole pickets that fully fit within the specified fence length are counted.
The calculation takes into account that no additional gap is required after the last picket. Therefore, the result corresponds to the actual linear arrangement rather than simply dividing the fence length by the sum of the picket width and gap.
Picket length. The ground clearance is subtracted from the total fence height. For example, with a fence height of 1800 mm and a ground clearance of 100 mm, the length of one picket is 1700 mm.
Total length. The total length of fence pickets is calculated by multiplying the number of whole pickets by the length of one picket. No additional allowance for cutting, damage or replacement elements is added automatically.
Posts and fence sections
Number of sections. The specified post spacing is treated as the maximum permitted distance between adjacent posts. If the fence length is not exactly divisible by this spacing, an additional section is added so that the entire fence length is covered.
Number of posts. A post is installed at the beginning and end of the fence line and between adjacent sections. Therefore, the number of posts is always one greater than the number of sections.
Standard spacing. With standard spacing, most sections have the specified length, while the last section may be shorter when necessary. For example, with a fence length of 10 m and post spacing of 3 m, the result is four sections and five posts.
Equal spacing. If equal post spacing is selected, the calculator keeps the required number of sections but distributes the total fence length evenly between them. For a 10 m fence with a specified maximum spacing of 3 m, this gives four equal sections of 2.5 m.
Post length
Length of one post. The required post length is the sum of the above-ground post height and the specified embedment depth. With a height of 1700 mm and an embedment depth of 700 mm, one post must therefore be 2400 mm, or 2.4 m, long.
Total length. The total length of posts is calculated from the length of one post and the number of posts. The selected embedment depth therefore directly affects the required amount of material.
Number and length of rails
Number of rows. The calculator supports a fence structure with 2 or 3 horizontal rail rows. Each fence section requires a separate rail segment in every row.
For example, four sections require 8 rail segments with two rows or 12 rail segments with three rows.
Total rail length. Each rail row runs along the entire fence length. Therefore, a 20 m fence requires 40 m of rails for two rows or 60 m for three rows.
Practical guidelines
Post spacing. Residential metal fences commonly use post spacing of about 2000-2500 mm. For taller fences, less wind-permeable panels or higher wind loads, smaller spacing is often used.
Number of rails. Two rows are commonly used for relatively low fences. Three rows are used for taller structures or where additional rigidity and an intermediate fixing point for the fence pickets are required.
Gap between pickets. There is no single universal value. The gap is selected according to the desired fence transparency, the width of the selected profile and wind permeability. Increasing the gap reduces the number of fence pickets required for the same fence length.
Ground clearance. The clearance reduces the length of each picket but does not affect their number along the fence. It is commonly selected with consideration for ground level variations, site maintenance and protection of the lower part of the fence from continuous contact with the ground.
Post embedment depth. The calculator uses the depth entered by the user without applying correction factors. In practice, the required depth should be selected with consideration for soil conditions, fence height, post dimensions, fixing method and wind loads.
What is included in the result
Fence pickets. The result includes only whole elements that fit within the specified fence length with the selected gap.
Posts. Their number is determined so that the entire fence line is divided into sections without exceeding the specified post spacing.
Rails. Their number depends on the number of fence sections and the selected 2 or 3 rows, while their total length depends on the fence length and the number of rows.
Material allowance. The calculator does not apply a specific waste or reserve factor. When purchasing materials, an additional allowance can be added separately for cutting, joints, possible defects and installation requirements.
Related European standards
Wind actions. For selecting post spacing, member dimensions and fixing arrangements in European practice, EN 1991-1-4, Eurocode 1: Actions on structures. Part 1-4: General actions. Wind actions is used.
Steel members. For checking metal posts and rails, EN 1993-1-1, Eurocode 3: Design of steel structures. Part 1-1: General rules and rules for buildings is applicable.
Foundations and soil. For assessing how posts are anchored in the ground, the relevant provisions of EN 1997-1, Eurocode 7: Geotechnical design. Part 1: General rules are used.
Fabrication of metal structures. Requirements for fabrication and execution of steel elements are covered by EN 1090-2. Execution of steel structures and aluminium structures. Part 2: Technical requirements for steel structures.
FAQs
Why can the last fence section be shorter than the others?
With standard post spacing, the calculator keeps the specified distance for the full sections. If part of the fence length remains, it forms a shorter final section. If equal section lengths are preferred, use the equal post spacing option.
What is the benefit of equal post spacing?
It avoids a short final section and creates sections of equal length along the entire fence. The calculator first determines the required number of sections and then distributes the total fence length evenly between them.
Why can changing post spacing affect the number of rails but not always their total length?
Smaller post spacing creates more fence sections, so the number of individual rail segments increases. However, each horizontal rail row still runs along the full fence length. Therefore, with the same fence length, the total length of one rail row remains unchanged.
How does ground clearance affect the fence picket calculation?
Ground clearance reduces the length of each picket and therefore the total length of picket material. It does not affect the number of pickets, which is determined by the fence length, picket width and gap between adjacent elements.
When should three rail rows be used instead of two?
Three rows are generally used for taller fences or when the unsupported length of the pickets between fixing points needs to be reduced. The final choice depends on the height and stiffness of the elements, post spacing and wind actions.