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Boards, rows, posts and fasteners for a horizontal board fence.
With these inputs:
| Result | Value |
|---|---|
| Boards needed | 186 |
| Board rows (up the height) | 13 |
| Boards to buy (16 ft) | 186 |
| Boards per row (joints on posts) | 13 |
| Offcut per board (ft) | 4 |
| Linear ft of board | 1,950 |
| Posts | 26 |
| Screws (approx.) | 744 |
| Board cost | $1,674 |
Horizontal boards sag between posts — keep line posts at 6 ft or under, or add a mid-span vertical stiffener.
Divides fence height by the board width plus gap to get the number of rows. Horizontal boards have no rails behind them, so every butt joint has to land on a post: each board covers as many whole post bays as its length allows, and the rest is offcut. Rows × boards per row, plus your waste percentage, is what to buy.
Boards = rows × ⌈bays ÷ ⌊board length ÷ post spacing⌋⌉ × (1 + waste %)
Multiply the number of rows by your fence length to get linear board feet, then divide by the board length you plan to buy. Every joint must land on a post, so count boards per row by whole post bays. A 6 ft tall, 150 ft fence using 5.5 inch boards with posts 6 ft apart needs 13 rows and about 186 boards with 10% waste — 12 ft boards (two bays each, no offcut) are the efficient buy.
6 ft on center is the practical maximum. Horizontal boards have no rails supporting them mid-span, so anything wider will visibly bow within a couple of seasons.
1x6 (5.5 inches actual) is the most common, with 1x4 and 1x8 used for narrower or wider looks. Thicker 5/4 stock resists cupping much better on spans over 6 ft.
Usually 15–30% more, because it needs more posts, longer boards and straighter lumber. Run the numbers against the wood fence calculator to compare your exact layout.
Horizontal board fences usually cost more than a vertical privacy fence of the same length — more posts, wider and straighter boards, and joints that must land on posts. Price the boards here, then use the install cost calculator for posts, concrete and labor.
Work out rows first: fence height in inches divided by board width plus gap, rounded up — 13 rows of 1x6 with a 1/4 inch gap on a 6 ft fence. Then posts: fence length divided by post spacing, plus one. Then boards: rows times boards per row, where each board covers whole post bays, plus 10% waste. A 100 ft, 6 ft tall fence on 6 ft posts with 12 ft boards takes 18 posts, 129 boards and about 515 screws.
With 1x6 boards and a 1/4 inch gap a 4 ft fence is 9 rows. On posts 6 ft apart using 12 ft boards that is 50 boards for 50 ft, 90 for 100 ft and 129 for 150 ft, each including a 10% allowance for culls.
Outside, facing the street or neighbor, is standard and looks best. Inside mounting is stronger but leaves the post faces showing.
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