Fence Picket Calculator
This free fence picket calculator tells you how many pickets to buy for your fence. Enter your total fence length, your picket width, and the gap between pickets — it instantly estimates the picket count, rounded up, plus the 2×4 rails you'll need for the frame.
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Results update as you type.
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Enter your fence dimensions to see the estimate.
How to use this calculator
Measure the total run of fence you want to build, in feet, and enter it as the fence length. Then enter the picket width in inches — a standard 1×6 picket is actually 5.5 inches wide, which is why that value is the default. Finally, set the gap between pickets: use 0 for a privacy fence, or 1 to 3.5 inches for a spaced or shadowbox style.
The calculator updates instantly as you type. The picket count is rounded up to a whole picket — you can't buy half a picket. The 2×4 rail count is a rough estimate based on two rails per 8-ft section; if your posts are spaced differently or your fence is over 6 ft tall (which usually needs three rails), adjust your shopping list accordingly.
How it works
Each picket plus its gap occupies picket width + gap inches of fence. The number of pickets is the total fence length in inches divided by that footprint, rounded up:
pickets = ceil(length in ft × 12 ÷ (picket width + gap))
Rounding up (the "waste/rounding note") matters because you must buy whole pickets. For example, a 50 ft fence with 5.5 in pickets and no gap: 600 ÷ 5.5 = 109.09, which rounds up to 110 pickets — the final picket covers the leftover fraction of the run.
The rail estimate assumes 2×4 rails mounted horizontally between posts, two rails per standard 8-ft section:
rails = ceil(length in ft ÷ 8) × 2
Both results are estimates. The picket count assumes a straight, continuous run with no gates and a uniform gap; subtract pickets for any gate openings. The rail count assumes 8-ft post spacing — measure your actual post layout before buying.
Frequently asked questions
How many pickets do I need for a fence?
Divide your fence length (in inches) by the width of one picket plus the gap between pickets, then round up: pickets = ceil(length in inches ÷ (picket width + gap)). For example, a 50 ft fence with 5.5 in pickets and no gap needs ceil(600 ÷ 5.5) = 110 pickets. Enter your numbers in the calculator above and it does the rounding for you.
What gap should I leave between fence pickets?
For a privacy fence, use a 0 in gap so pickets butt together (or overlap for board-on-board styles). For a spaced picket or shadowbox fence, a common gap is 1 to 3.5 in. A larger gap needs fewer pickets but gives less privacy, so pick the gap before you estimate and use the same gap when you build.
How many rails does a fence need?
Most wood fences use two horizontal 2×4 rails per 8-ft post section (three rails for fences over 6 ft tall). The estimate used here is 2 rails per 8-ft section: rails = ceil(fence length ÷ 8) × 2. It assumes 8-ft post spacing — measure your actual post layout for a tighter count.
Should I buy extra pickets beyond the calculator count?
Yes — buy 5 to 10% extra. The calculator already rounds up, but pickets can be warped, split, or damaged, and the estimate doesn't account for gates or end-of-run cuts. A few spares also let you replace individual pickets later without hunting for a matching batch.