Fence Calculator
Estimate the materials for a wood privacy fence — posts, fast-setting concrete, pickets and rails — for any length and height.
A 100 ft fence with 8 ft post spacing needs 14 posts and about 2 bags of 50 lb fast-setting concrete per post.
How to Use This Fence Calculator
- Enter the total fence length in feet.
- Choose the post spacing — 8 ft is typical; 6 ft for windy areas.
- Enter the post height to get the recommended hole depth (about 1/3 of the post length).
- Read the totals: posts, 50 lb fast-setting bags, pickets and rails.
The Formula
Posts = fence length ÷ spacing, rounded up, plus one for the end. Concrete per post reuses the concrete post-hole math: for a 6 ft post, dig an 8 in hole 24–30 in deep and use about 2 bags of 50 lb fast-setting mix. Pickets depend on board width plus gap.
Posts = ceil(L ÷ spacing) + 1e.g. 100 ft ÷ 8 ft = 12.5 → 13 + 1 = 14Hole ≈ 1/3 of post height6 ft post → 2 ft deep holeConcrete ≈ 2 bags/post50 lb fast-setting, hole 3× post diameterPickets = ceil(L × 12 ÷ (width + gap))1×6 pickets (5.5 in) with 3 in gapWorked Example: 100 ft Fence
A 100 ft fence with 8 ft spacing: 100 ÷ 8 = 12.5 → 13, plus 1 = 14 posts. At 2 bags of 50 lb fast-setting concrete per post: 28 bags. With 1×6 pickets 3 in apart: 100 × 12 ÷ 8.5 = 141.2 → 142 pickets.
Materials by Fence Length
| Fence length | Posts (8 ft spacing) | 50 lb fast-setting bags | Pickets (1×6, 3 in gap) |
|---|---|---|---|
| 100 ft | 14 | 28 | 142 |
| 150 ft | 20 | 40 | 212 |
| 200 ft | 26 | 52 | 283 |
2 bags of 50 lb fast-setting concrete per post. Pickets rounded up.
Setting Posts: Depth and Concrete
The golden rule: bury about one third of the post length. A 6 ft post gets a 24 in hole; an 8 ft post gets a 32 in hole. Make the hole about 3× the post diameter — an 8 in hole for a 4×4 post. Use fast-setting concrete in 50 lb bags: about 2 bags per post for a 6 ft fence, poured dry and watered in.
Quick Tips
- Space posts 6–8 ft apart — 8 ft for solid fences, 6 ft in windy areas.
- Set corner and gate posts first, then run a string line between them.
- Pressure-treated lumber lasts longest in ground contact.
Frequently Asked Questions
How far apart should fence posts be?
6 to 8 ft apart is the standard. 8 ft works for most wood fences; use 6 ft spacing in windy areas or with heavy pickets.
How deep should a fence post hole be?
About one third of the post length. A 6 ft post needs a 24 in hole; an 8 ft post needs 32 in.
How much concrete do I need per fence post?
About 2 bags of 50 lb fast-setting concrete for a typical 6 ft fence post with an 8 in hole.
How many pickets do I need for a 100 ft fence?
About 142 pickets of 1×6 (5.5 in wide) spaced 3 in apart.