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Fence Calculator
Enter your fence length to get a materials count for a standard wood privacy fence: how many sections, posts, horizontal rails and individual pickets. Post spacing, rail count and picket dimensions are all adjustable to match your design.
Results update as you type. Estimates only — confirm final quantities before ordering.
The formula
Posts = Sections + 1
Rails = Sections × Rails per section
Pickets = (Length in inches) ÷ (Picket width + Gap)
The +1 post is the one everyone forgets: a run of fence has a post at both ends of every section, so posts always outnumber sections by one per continuous run. Corners and gate openings each add their own posts on a real layout — treat this count as the straight-run baseline. The picket count assumes pickets run the full length with no gate opening deducted.
Worked example
Example: a 120 ft fence, posts every 8 ft, 2 rails per section, 5.5 in pickets with a 0.5 in gap.
- Sections: 120 ÷ 8 = 15 sections
- Posts: 15 + 1 = 16 posts
- Rails: 15 × 2 = 30 rails
- Pickets: (120 × 12) ÷ (5.5 + 0.5) = 240 pickets
Reference chart
| Fence length | Posts | Sections | Rails | Pickets |
|---|---|---|---|---|
| 40 ft | 6 | 5 | 10 | 80 |
| 60 ft | 9 | 8 | 16 | 120 |
| 80 ft | 11 | 10 | 20 | 160 |
| 100 ft | 14 | 13 | 26 | 200 |
| 120 ft | 16 | 15 | 30 | 240 |
| 150 ft | 20 | 19 | 38 | 300 |
| 200 ft | 26 | 25 | 50 | 400 |
Frequently asked questions
What is the standard spacing for fence posts?
Eight feet on center is typical for wood privacy fences with 4×4 posts; six feet is used for taller fences, windy sites, or heavier pickets. Wider spacing saves posts but lets rails sag over time.
How do gates change the count?
A gate replaces pickets across its width and needs two stout gate posts plus hinges and a latch. Subtract the gate width from the fence length before calculating pickets, and add the gate posts and hardware separately.
What about a board-on-board (overlapping) fence?
Overlapping pickets cover less per board. Enter the picket's effective coverage — its width minus the overlap, commonly about 1 inch — as the picket width, and set the gap to 0. The rest of the math is unchanged.
How much concrete does each post need?
Plan on roughly one to two 50–60 lb bags of fast-setting concrete per post hole, depending on hole diameter and depth. Concrete is not included in the counts above — multiply your post count by the per-hole figure for your hole size.
Related calculators
- Board Foot Calculator — Board feet and lumber cost from thickness, width, length and quantity.
- Concrete Calculator — Cubic yards and bag counts for slabs, patios and pads.
- Mulch Calculator — Mulch in cubic yards and standard 2 cu ft bags.
Sources & method: Standard fence estimating practice (posts = sections + 1 per run); cross-checked against Inch Calculator — Fence Calculator.