Fence calculator
Posts, rails and pickets for a wood fence, and the concrete to set the posts.
A 100 ft wood fence 6 ft high takes 14 posts of 8 ft, 39 rails and 219 pickets, with 27 bags of 80 lb concrete for the posts.
Measure
You need
8 ft long, 2 ft in the ground · 13 sections
Your shopping list
Rails
39 rails
8 ft long, 3 per section
Pickets
219 pickets
6 ft long, 5.5 in wide
Concrete for the posts
27 bags of 80 lb (36 kg)
or 43 bags of 50 lb (23 kg), holes 3 × the post width
Everything is calculated in your browser. Nothing you type is sent anywhere.
How it is calculated
- Sections100 ÷ 8 ft, rounded up = 13
- Posts13 + 1 + 0 corners = 14, 8 ft long
- Rails13 × 3 = 39
- Pickets1,200 in ÷ (5.5 + 0) = 219
Materials by fence length
6 ft high, straight run, posts 8 ft apart, 5.5 in pickets butted, 4×4 posts.
| Length | Posts | Rails | Pickets | 80 lb bags |
|---|---|---|---|---|
| 25 ft | 5 | 12 | 55 | 10 |
| 50 ft | 8 | 21 | 110 | 16 |
| 75 ft | 11 | 30 | 164 | 21 |
| 100 ft | 14 | 39 | 219 | 27 |
| 150 ft | 20 | 57 | 328 | 38 |
| 200 ft | 26 | 75 | 437 | 50 |
Post length and depth by fence height
| Fence height | Post length | In the ground | Rails per section |
|---|---|---|---|
| 3 ft | 4 ft | 12 in | 2 |
| 4 ft | 5.3 ft | 16 in | 2 |
| 5 ft | 6.7 ft | 20 in | 2 |
| 6 ft | 8 ft | 24 in | 3 |
| 8 ft | 10.7 ft | 32 in | 3 |
Frequently asked questions
How many posts do I need for a 100 ft fence?
14 posts for a straight run with posts 8 ft apart: 13 sections plus one. Add one post for every corner.
How deep should fence posts be?
Bury one third of the height above ground (NDSU Extension): a 6 ft fence takes 8 ft posts set 2 ft deep, a 4 ft fence takes posts of 5 ft 4 in set 16 in deep.
How far apart should fence posts be?
Up to 8 feet apart (NDSU Extension), which matches 8 ft rails. Use 3 rails per section for a solid fence 6 ft or higher, 2 below that.
How many pickets for a 100 ft fence?
219 pickets of 5.5 in (a 1×6) butted together, 200 with a ½ in gap: length in inches ÷ (picket width + gap), rounded up.
How much concrete per fence post?
A 4×4 post in a 10.5 in hole 2 ft deep takes 1.03 ft³ of concrete, so 2 bags of 80 lb or 4 of 50 lb per post with 10 % extra (QUIKRETE yields).