Posts, rails and concrete for 400 ft
3 rails per section, 10-inch holes 24 inches deep, 50 lb fast-setting concrete.
| Post spacing | Posts | Sections | Rails | Concrete bags |
|---|---|---|---|---|
| 8 ft | 51 | 50 | 150 | 126 |
| 6 ft | 68 | 67 | 201 | 167 |
Pickets
- Privacy fence (5.5 in pickets, no gap): 873 pickets
- Picket fence (5.5 in pickets, 2.5 in gaps, 2 rails): 600 pickets and 100 rails
400 ft is roughly a large yard or a property line run. Each gate replaces a section of pickets but needs its own sturdy posts — many builders use 4×6 or doubled posts at gates.
Concrete options
Each post hole takes about 0.92 cu ft of concrete: 2.5 bags of 50 lb fast-setting mix or 1.5 bags of 80 lb standard mix per post. For all 51 posts, buy about 126 bags of fast-setting or 79 bags of 80 lb mix.
The math
Common questions
How many posts for a 400 ft fence?
51 posts at 8 ft spacing, or 68 posts at 6 ft spacing.
How many pickets for 400 feet of fence?
873 pickets for a privacy fence with 5.5-inch pickets and no gaps.
How much concrete for a 400 ft fence?
About 126 bags of 50 lb fast-setting concrete or 79 bags of 80 lb mix, using 10-inch holes 24 inches deep.
Want the full method, tips and other sizes? See the fence calculator guide.