100 ft fence, 8 ft spacing, 1 gate of 4 ft, 3 rails, 5.5 in pickets
14 posts, 36 rails, 210 pickets and 28 bags of concrete.
Fence calculator
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A straight wood fence with posts at an even spacing, each gate adding one extra post, rails running between posts and pickets set side by side with the gap you enter. Gates themselves are not counted in the pickets.
ft
Post spacing
Rails per section
ft
inches
inches
About 2 bags of 50 lb for a 4 × 4 post in a 10 in hole.
Posts
14
96 ft of fence in 12 sections of up to 8 ft, plus 1 gate. You need 36 rails, 210 pickets and 28 bags of concrete.
- Rails
- 36
- Pickets
- 210
- Concrete bags
- 28
- Sections
- 12
Shopping list
| Item | Quantity | Note |
|---|---|---|
| Posts | 14 | 8 ft apart, 1 extra per gate |
| Rails | 36 | 3 per section, 8 ft long |
| Pickets | 210 | 5.5 in wide, 0 in gap |
| Concrete, 50 lb bags | 28 | 2 per post |
| Gates | 1 | 4 ft wide |
Counting fence materials
A wood fence has a simple structure: posts set in the ground, rails running between them, and pickets fixed to the rails. Once you know the length and the post spacing, everything else follows.
Take 100 ft of fence with one 4 ft gate. That leaves 96 ft of fence, which at 8 ft spacing is 12 sections. A straight run of 12 sections needs 13 posts, and the gate adds one more, for 14. With three rails per section you need 36 rails. Pickets 5.5 inches wide with no gap need 210 for 96 ft. At two bags of concrete per post, buy 28 bags.
Corners and ends are where most mistakes happen. Every corner needs its own post, so if your fence turns, add the sides up separately or add a post per corner. Heavy gates often get a thicker post.
Check local rules before you dig. Many towns limit fence height, and utility lines must be marked before you put in posts.
Sources
What this calculator does not account for
- Corners need extra posts.
- Check local height rules and buried lines before digging.
How this is calculated
Formula: Posts and pickets
posts =round up(fence run ÷ spacing) + 1 + gates; pickets =round up(fence run × 12 ÷ (picket width + gap))What the symbols mean
- fence runFence length minus the width of the gates, in feet.
- spacingDistance between posts, usually 6 or 8 ft.
Good to know
- Rails = sections × rails per section.
- Concrete bags = posts × bags per post.
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Worked examples
Each example is worked out by the same code as the calculator above.
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<iframe src="/embed/fence-calculator" title="Fence calculator" width="100%" height="720" style="border:0;max-width:42rem" loading="lazy"></iframe>Questions
How many fence posts for 100 feet?
With 8 ft spacing and one 4 ft gate, 14 posts.
How far apart should fence posts be?
6 to 8 ft. 8 ft is common for wood fences; use 6 ft in windy places or for heavy panels.
How many bags of concrete per fence post?
About two 50 lb bags for a 4 × 4 post in a 10 inch hole about 2 ft deep.
How deep should fence posts go?
About a third of the post's height above ground, often 2 to 3 ft, and below the frost line in cold climates.
How many rails does a 6 ft fence need?
Three: top, middle and bottom.