How to use this fence calculator
- Measure the total length of the fence line.
- Choose the post spacing: 8 ft is standard for wood fences, 6 ft for heavy or tall fences.
- Enter the picket width and gap (0 for a solid privacy fence).
- Post holes are typically 3 times the post width and 1/3 of the post length deep (at least 24 in).
Example
A 150 ft privacy fence with posts every 8 ft and one gate needs 21 posts, 38 rails, 328 pickets and about 63 bags of fast-setting concrete.
What to know before you buy
Common fence styles
A privacy fence uses tightly spaced pickets to block views. A picket fence has gaps between boards and is usually 3–4 ft tall. Board-on-board fences overlap pickets on both sides for full privacy even as wood shrinks. Chain-link and vinyl fences have their own post spacing and parts.
Posts and footings
Use 4×4 pressure-treated posts rated for ground contact for most wood fences, and 6×6 for gates or tall fences. Set posts in concrete or compacted gravel, at least one third of their length deep and below the frost line in cold climates.
Wood fence materials (8 ft spacing, 2 rails, 5.5 in pickets, 1 gate)
| Fence length | Posts | Rails | Pickets |
|---|---|---|---|
| 50 ft | 9 | 14 | 110 |
| 100 ft | 15 | 26 | 219 |
| 150 ft | 21 | 38 | 328 |
| 200 ft | 27 | 50 | 437 |
| 300 ft | 40 | 76 | 655 |
Formula
Sections = length ÷ post spacing; posts = sections + 1 (plus one extra per gate). Pickets = length ÷ (picket width + gap). Concrete = (hole volume − post volume) ÷ 0.375 cu ft per 50 lb bag, for 4×4 posts.
Tips from the pros
- Call 811 before digging to have underground utilities marked.
- Set the corner and end posts first, then run a string line to align the others.
- Check property lines and any HOA or city height limits before you build.
Common mistakes to avoid
- Setting posts too shallow: bury at least one third of the post length.
- Forgetting gate posts, which need to be stronger and set deeper.
Frequently asked questions
How far apart should fence posts be?
Usually 6 to 8 feet. Closer spacing makes a stronger fence, especially in windy areas.
How much concrete per fence post?
Two to three 50 lb bags of fast-setting concrete for a 4×4 post in a 10 in wide, 2 ft deep hole.
How many pickets do I need for 100 feet of fence?
With 5.5 inch pickets and no gaps, about 219 pickets.
How deep should fence posts be?
At least one third of the post length and below the frost line; for a 6 ft fence with 8 ft posts, dig about 2–3 ft.