Start from the run length, then divide by the spacings
Everything keys off the total fence length. Find your run (measure it, or use 2 × (length + width) for a rectangle), subtract the width of any gates, then divide by the post spacing for posts and by the panel length for panels. Pickets and rails come from the panels.
Worked example: a 50 × 30 ft rectangle, wood, 6 ft spacing
- Run. 2 × (50 + 30) = 160 ft around the yard.
- Posts. 160 ÷ 6 ≈ 27 posts (a closed loop needs about one post per section).
- Panels / sections. 160 ÷ 6 ≈ 27 panels at 6 ft each.
- Pickets. 4″ wide over 160 ft: 160 × 12 ÷ 4 = 480 pickets.
- Rails. 2 per panel up to 5 ft, 3 per panel for 6 ft and taller. Here 27 × 2 = 54 rails.
Spacing and depth by fence type
| Fence type | Post spacing | Post depth |
|---|---|---|
| Wood (pickets) | 6 ft (4–8 ft) | 24–36″ |
| Vinyl | 6–8 ft | ~30″ |
| Chain-link | 8–10 ft | 24″ |
| Aluminum | 6 ft (4–8 ft) | 24″ |
Post spacing over 8 ft tends to sag and is the most common structural mistake. Chain-link is sold by the linear foot rather than in panels.
Before you order
- Rails scale with height. Use 2 rails per panel for a 4–5 ft fence, 3 for 6 ft and up.
- Gates replace a section. Subtract each gate's width from the run before counting panels, and keep a gate to 3–4 ft so the hinges hold.
- Add 10–15% on materials. Cuts, uneven ground and the odd warped board eat into a tight count.
Common questions
How many posts do I need for 100 feet of fence?
At the standard 6-foot spacing, 100 divided by 6 is about 17 sections, so you need roughly 17 posts for a closed loop and 18 for a straight open run (the run needs one extra post to close the last section).
How many pickets fit on a 6-foot panel?
With 4-inch pickets and no gap, a 6-foot (72-inch) panel takes 18. Adding a small spacing gap reduces that; a picket plus a half-inch gap gives about 16 per panel.
How deep should the posts go?
About one third of the fence height, and at least 24 to 30 inches. A 6-foot fence wants roughly 24 to 36 inches of post in the ground, deeper in soft or wet soil.
