Softonic

Fence Calculator

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Buying fence materials by guesswork means a second trip to the lumberyard, or a pile of leftover pickets. This calculator turns a run length, post spacing and picket width into a clean shopping list: how many posts to set, how many rails to run, how many pickets to cut, and how many bags of concrete to anchor it all. Enter your numbers and the counts update instantly, so you can price the whole job before you dig the first hole.

How to calculate fence materials

  1. 1

    Measure the run

    Enter the total fence length in feet and the spacing between posts (6 to 8 ft is typical for wood fences).

  2. 2

    Set the build

    Choose 2 or 3 rails per section, then enter the picket width and the gap you want between pickets, both in inches.

  3. 3

    Read the list

    See posts, total rails, pickets, sections and concrete bags: round up and you have your order.

The formulas

The calculator counts each material directly from your inputs:

  • Sections = ceil(fence length ÷ post spacing), the number of gaps between posts.
  • Posts = sections + 1, one extra post closes the final section.
  • Rails = sections × rails per section, every section carries the same number of horizontal rails.
  • Pickets = ceil(fence length × 12 ÷ (picket width + gap)), length is converted to inches so it matches the picket dimensions.
  • Concrete bags = posts × 1, one bag per post hole as a baseline; wider or deeper holes need more.

Worked example

Say you are fencing a 100 ft run with posts every 8 ft, 3 rails per section, 5.5 in pickets and no gap:

  • Sections = ceil(100 ÷ 8) = 13
  • Posts = 13 + 1 = 14
  • Rails = 13 × 3 = 39
  • Pickets = ceil(100 × 12 ÷ 5.5) = ceil(1200 ÷ 5.5) = 219
  • Concrete bags = 14 × 1 = 14

Quick reference

Fence length Post spacing Sections Posts Pickets (5.5 in, no gap)
50 ft 8 ft 7 8 110
100 ft 8 ft 13 14 219
150 ft 6 ft 25 26 328
200 ft 8 ft 25 26 437

Pitfalls to avoid

  • Forgetting the last post. A run always needs one more post than it has sections, the calculator already adds it.
  • Ignoring the gap. A 3/8 in shadow gap between pickets adds up fast and lowers your picket count; enter it so the math stays honest.
  • Under-buying concrete. One bag per post is a minimum. Corner, gate and end posts usually want two bags and a deeper hole.
  • Skipping waste. Add 5–10% extra pickets for bad cuts, warped boards and future repairs.

Frequently Asked Questions

For wood privacy and picket fences, 6 to 8 ft on center is standard. Closer spacing makes a stiffer, stronger fence; 8 ft is the common maximum before rails start to sag.

Divide 12 by the picket width plus the gap, both in inches. With 5.5 in pickets and no gap that is about 2.2 pickets per foot, so a 100 ft fence needs roughly 219 pickets.

One 50 lb bag of fast-setting concrete per post is a reasonable baseline for a standard hole. Larger posts, gate posts and corners typically need two bags and a wider, deeper hole.

The numbers you enter are sent to our server as part of the normal page interaction so the results can be calculated, and they are included in the page link when you move through the calculator steps. They are not stored, saved or shared.

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