Fence calculator
Enter the fence line and panel width — get panel count, post count and the concrete to set them, in one pass.
Result
Fence materials
How many fence panels and posts?
Formula
panels = fence length ÷ panel width · posts = panels + 1
concrete = posts × 2–3 bags (50 lb)
Example — 100 ft of privacy fence: 100 ÷ 8 = 13 panels, 14 posts, 42 bags of 50 lb concrete (3/post for 6 ft). Add a bag or two per gate post.
Checklist before you dig
- Call 811 (US) before digging
- Post depth: ⅓–½ of above-ground height, minimum to frost line; 6 ft fences → 30–36 in holes. Details and per-post math: post hole calculator.
- 6 in of gravel under each post for drainage; use rated-for-ground-contact lumber (UC4A) or galvanized steel posts.
- Check local rules: heights, setbacks, and pool enclosures (4 ft minimum, self-latching gate) are code items.
- Property line disputes cost more than fences — verify before line-setting.
Cost reality
| Fence type | DIY materials /ft | Installed /ft |
|---|---|---|
| Wood privacy 6 ft | $10–18 | $20–40 |
| Cedar picket 4 ft | $8–14 | $16–30 |
| Chain link 4 ft | $6–10 | $12–20 |
| Aluminum 4 ft | $15–25 | $30–55 |
Frequently asked questions
How many fence posts do I need for 100 feet?
At 8 ft spacing: 14 posts (13 sections + 1). At 6 ft: 18 posts.
How many bags of concrete per fence post?
2×50 lb bags for 4 ft fences, 3 for 6 ft (10 in hole, 30 in deep). The post hole calculator fine-tunes by hole size.
How far apart should fence posts be?
8 ft max for wood panels; 6 ft in high-wind areas or with 4×4 pine (use 3 braces per panel otherwise). Steel-post systems go 8–10 ft.
How much does a 100 ft privacy fence cost?
DIY: $1,000–1,800 materials. Installed: $2,000–4,000+. The cost panel above computes either basis.
Should fence posts be set in concrete or gravel?
Concrete for standard wood fences; compacted gravel works in well-drained soils and lets posts dry (rot-resistant species only). Either way: 6 in of drainage gravel in the hole bottom.