How Many Posts and Pickets for 100 Feet of Fence?
Posts needed
14 posts
Posts at 8 feet, three rails per section, 5.5 inch pickets butted tight.
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How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Total fence length100 ft
- Post spacing8 ft
- Rails per section3
- Picket width, 0 for panels5.5 in
- Gap between pickets0 in
- Post hole depth30 in
- Post hole diameter10 in
Posts needed14 posts
| Sections | 13 |
|---|---|
| Posts, plus one per corner and gate | 14 |
| Rails | 39 |
| Pickets | 219 |
| Concrete per hole | 1.15 cu ft |
| 50 lb concrete bags, whole job | 56 |
The material list this produces
| Posts | 14 |
|---|---|
| Rails | 39 |
| Pickets | 219 |
| Concrete, 50 lb bags | 56 |
Post spacing compared
Closer posts mean a stiffer fence and a bigger post and concrete bill. Same run, three spacings.
| Post spacing | Posts needed | 50 lb concrete bags, whole job |
|---|---|---|
| 6 ft | 18 posts | 72 |
| 7 ft | 16 posts | 64 |
| 8 ft | 14 posts | 56 |
What else matters here
A hundred feet at 8 foot spacing is 13 sections and 14 posts, counting the one on the far end. Add one more post for every corner and every gate, because a corner post carries two runs and a gate post carries a moving load all day.
Fifty six bags of concrete sounds like a lot for a hundred feet, and it is the honest number for a 30 inch hole at 10 inch diameter. If that is out of budget, the answer is a smaller diameter hole, not a shallower one: depth is what resists frost and wind, and diameter is mostly what costs money.
Set the posts, let them cure, then rail and picket. Hanging rails off green concrete is how a fence ends up with a wave in it that no amount of picket work will hide.
What this calculator assumes
- Sections are the length divided by the spacing, and posts are sections plus one. Corners and gates each add a post on top of that.
- Concrete per hole is the hole volume less the post, figured at a 4x4. Two 50 lb bags per hole is the common shortcut and it is close.
- Set posts a third of their length in the ground in frost country, and check your local frost depth before you dig.
Questions people ask
How many posts for 100 feet of fence?
About 14 at 8 foot spacing, plus one extra for each corner and each gate post.
How deep should fence posts be?
A third of the post length or below the local frost line, whichever is deeper. Thirty inches is a common figure but frost depth is regional, so check locally.
How many bags of concrete per fence post?
About four 50 lb bags for a 10 inch hole at 30 inches deep. Wider or deeper holes go up quickly, since volume scales with the square of the diameter.
The fence calculator takes any dimensions you like and hands back the same list.