Loan Fence Estimator
A fence is three shopping lists in a trench coat: structure (posts and rails), skin (pickets), and the concrete that holds it up. Enter the run and this estimator splits it into all three.
Picket width is the actual board width — a nominal 1×6 picket really measures 5.5 in. Set the gap to 0 for a board-on-board look and the count rises accordingly (and true board-on-board needs about 40% more again for the overlap layer).
How it works
Posts come first: the run is divided into sections no longer than your spacing — 100 ft at 8-ft spacing is 13 sections, and sections + 1 = 14 posts (every run has a post at both ends; corner and gate posts are included in that count for a straight run). Rails are sections × rails per section. Pickets cover the run minus 4 ft per gate: each picket covers its width plus one gap — a 5.5-in picket at a ½-in gap covers 6 in, exactly 2 per foot. Concrete is figured at 1½ 80-lb bags per post, the standard planning figure for a typical 10-in × 30-in hole in average soil.
Formula & worked example
Formula: Sections = fence length ÷ post spacing, rounded up; posts = sections + 1; rails = sections × rails per section. Pickets = (length − 4 ft per gate) × 12 ÷ (picket width + gap, in inches). Concrete = posts × 1.5 bags (80-lb).
Worked example: A 100-ft fence at 8-ft spacing with 5.5-in pickets, a ½-in gap and one gate: 13 sections, 14 posts, 26 rails, 192 pickets (the gate removes 4 ft of pickets) and 21 bags of concrete.
When to use this
- Fencing a yard and splitting the order into posts, rails, pickets and concrete.
- Checking a fence contractor's materials list line by line.
- Planning a DIY weekend build — including how many concrete bags the truck must carry.
- Comparing 6-ft vs 8-ft post spacing on strength and price.
How to use it, step by step
- Measure the run in feet, gate positions included.
- Choose post spacing: 8 ft standard, 6 ft for wind, height or heavy gates.
- Enter your picket's actual width and the gap you want (0 for solid).
- Set the gate count — each removes 4 ft of pickets but keeps its posts.
- Buy posts, rails and pickets from the result; add post caps and hardware separately.
What the inputs mean
| Input | What it is | Typical values |
|---|---|---|
| Fence length | Total run including gate spans | Yard fences 40–200 ft |
| Post spacing | Section length; shorter = stronger, more posts | 8 ft standard, 6 ft heavy-duty |
| Picket width & gap | Actual board width and the space between | 5.5 in wide, ¼–½ in gap |
| Rails per section | Horizontal supports per bay | 2 under 6 ft tall, 3 above |
| Gates | 4-ft openings that skip pickets | 1–2 typical |
Another worked example
A side-yard run: 60 ft, 6-ft spacing for a windy corner lot, narrow 3.5-in pickets at a ¼-in gap, no gates. That is 10 sections, 11 posts, 20 rails — and the same 192 pickets as the default fence, because narrower pickets at tighter gaps cover the same foot. Concrete: 17 bags.
Frequently asked questions
How many pickets do I need for 100 feet of fence?
With 5.5-in pickets at a ½-in gap, each picket covers 6 in — 2 per foot. One 4-ft gate opening leaves 96 ft to cover: 192 pickets. Drop the gap to zero and the same run takes 210.
How far apart should fence posts be?
Eight feet is the residential standard for wood privacy fences; six feet is the upgrade for windy sites, tall fences or heavy gates. The estimator defaults to 8 ft — a 100-ft run needs 14 posts at 8-ft spacing, 18 at 6-ft.
How much concrete per fence post?
Plan on 1½ 80-lb bags per post for a standard hole (about 10 in wide and 30 in deep) — 21 bags for the 14-post default fence. Gate and corner posts deserve the full 2 bags.
How many rails do I need?
Two rails per section for fences up to 6 ft tall, three above that or where pickets are heavy hardwood. The default fence — 13 sections, 2 rails — needs 26 rails, sold as 8-ft boards matching the section length.
Does the gate change the post count?
Not in this estimator — a standard gate hangs between two posts that are already in the run count, and its opening simply removes 4 ft of pickets per gate. Wide double gates need their own heavier posts; add two 6×6 posts separately.
🪵 Buying lumber by the board foot?
Posts and rails are easy counts — rough lumber for the gate frame is sold differently. The Board Foot Estimator turns dimensions into board feet and cost.
How deep should fence posts be set?
The rule is one-third of the post in the ground, and below the frost line where that is deeper: a 6-ft fence typically uses 8-ft posts with 2 ft buried. In frost country the hole depth follows the frost line, not the rule of thumb.
Wood, vinyl or composite — does the math change?
The post and rail structure is the same; the skin changes. Vinyl and composite fences come as 6- or 8-ft panels instead of pickets: divide the run (minus gates) by the panel width for the panel count, and the post count here still applies.