How Many Fence Boards Do I Need?

Quick answer: Divide your total fence length (in inches) by the board width plus any gap. For a 100-foot privacy fence using 5.5-inch pickets with no gap, you need about 219 pickets, 14 posts, and 28 rails.

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The Formula (Step by Step)

Step 1: Calculate Pickets

Total fence length (inches) ÷ (board width + gap) = number of pickets

Example: 100 ft = 1,200 inches
1,200 ÷ 5.5 = 218.2 → round up to 219 pickets

Step 2: Calculate Posts

Total fence length ÷ post spacing + 1 = number of posts

Standard post spacing is 8 feet.
100 ÷ 8 + 1 = 13.5 → round up to 14 posts

Step 3: Calculate Rails

Number of sections × rails per section = total rails

13 sections × 2 rails = 26 rails (use 3 rails per section for fences 6 ft+ tall → 39 rails)

Step 4: Calculate Post Concrete

Each post needs 1–2 bags of 50 lb concrete mix (for a standard 4×4 post, 24-inch deep hole).
14 posts × 1.5 bags = 21 bags

Common Fence Board Sizes

Dog-ear pickets (most common): 5.5 inches wide × 6 ft tall
1×6 boards: Actual width 5.5 inches
1×4 boards: Actual width 3.5 inches (used for picket fences)
Shadowbox: Same picket count × 2 (boards on both sides, offset)

Full Material List (100 ft Privacy Fence, 6 ft Tall)

Pickets: 219 dog-ear boards (5.5" × 6')
Posts: 14 pressure-treated 4×4 × 8' (buried 2 ft)
Rails: 39 pressure-treated 2×4 × 8' (3 per section)
Concrete: 21 bags (50 lb)
Screws/nails: ~10 lbs of 1.5" exterior screws
Estimated cost: $1,200–$2,000 (materials only)

Common Mistakes to Avoid

❌ Forgetting about the gate

Subtract gate width from your fence run, but add a gate kit to your list. Gates need extra posts (4×4 minimum, 6×6 for wide gates) and heavy-duty hinges.

❌ Using untreated wood for posts

Always use pressure-treated or cedar for ground contact. Regular pine will rot in 2–3 years. Posts should be rated for ground contact (UC4A or higher).

❌ Setting posts too shallow

Bury posts ⅓ of their total length or at least 24 inches deep — whichever is more. In cold climates, go below the frost line.

❌ Not adding 10% for waste

Boards split, knots happen, and cuts create scrap. Buy 10% extra pickets.

Pro Tips

Check your property line. Survey stakes save lawsuits. Most jurisdictions require fences to be inside your property line.
Call 811 before digging. Free utility locating service. Hitting a gas line is not a DIY moment.
String a line. Use mason's line between corner posts to keep everything straight. Your eye isn't as good as you think.
Boards should face the neighbor. The "good side out" rule is often a local code requirement, not just courtesy.

Frequently Asked Questions

How much does a wood fence cost per foot?

DIY materials run $12–$20 per linear foot for a 6-foot privacy fence. Professional installation doubles or triples that to $25–$50 per foot.

How far apart should fence posts be?

8 feet on center is standard for most wood fences. Some prefer 6 feet for extra strength, especially in windy areas. Never exceed 8 feet — the rails will sag.

Do I need a permit to build a fence?

Usually yes for fences over 4 feet tall. Check with your local building department. HOAs may have additional restrictions on style, height, and materials.

How long does a wood fence last?

Pressure-treated pine: 15–20 years. Cedar: 15–25 years. Proper maintenance (staining every 2–3 years) extends life significantly.

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