Fence Board Dimensions: Picket Widths, Thickness and Lengths

A “1×6” fence picket is not 1 inch thick or 6 inches wide, and that gap between label and reality is where most board counts go wrong. Understanding fence board dimensions lets you buy the right quantity the first time, avoid an extra trip to the lumberyard, and space pickets evenly from post to post. In short: a 1×6 picket actually measures about 5.5 inches wide, a 1×4 measures about 3.5 inches, and the popular dog-ear picket is often 5/8 inch thick rather than a full 3/4 inch.

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Length is the other half of the equation. Pickets are sold in lengths that match common fence heights (4, 5, 6 and 8 feet), and you choose a length based on how high the fence should stand and how much clearance you want at the ground. Get width, thickness and length straight, and counting boards becomes simple arithmetic.

Nominal vs Actual Fence Board Dimensions

Lumber is named by its rough-sawn size before drying and planing. Once milled smooth, it shrinks. Fence boards follow the same rule, though fence-grade pickets are sometimes milled even thinner than standard boards to save cost.

Rough-sawn cedar is the exception worth knowing. Because it is not planed smooth, a rough cedar 1×6 can measure close to a full 1 inch thick and 5.5 to 5.75 inches wide. Always measure a sample board from the actual pile you are buying, since widths can drift by 1/8 inch between mills.

Thickness matters more than it looks

A 5/8 inch picket is lighter and cheaper, and it works fine for most privacy fences with rails spaced 24 inches or less apart. A full 3/4 inch board resists cupping and warping better, holds fasteners more securely, and is the better pick for horizontal fences where boards span 6 to 8 feet between posts. If your area sees strong sun on one side of the fence, thicker boards will stay flatter.

Picket Styles and Their Sizes

• Dog-ear: Corners clipped at 45 degrees. Usually 5/8 x 5.5 inches, sold in 4, 5 and 6 foot lengths. The most common privacy fence picket.
• Flat top: Square ends, available in 1×4, 1×6 and 1×8, often used for modern or board-on-board designs.
• Gothic or French gothic: Pointed decorative tops, usually 1×4 or 1×3, in 3 to 4 foot lengths for picket fences.
• Tongue and groove: Interlocking edges for zero gaps; the exposed face is narrower than the full board width, so count by face width.
• Horizontal fence boards: Typically 1×6 in 8 to 16 foot lengths so a single board can span two or more posts.

Picket Lengths for 4, 6 and 8 Foot Fences

The picket length you buy is usually the same as the fence height, but the finished height depends on ground clearance and whether the pickets extend above the top rail.

• 4 foot fence: 4 foot pickets, or 42 inch pickets if you want a 3.5 foot decorative picket fence with 2 inches of ground clearance.
• 6 foot fence: 6 foot (72 inch) pickets. Leave about 2 inches above the soil so the bottom stays dry, giving a finished height near 6 feet 2 inches at the post top if posts are cut at 74 inches, or a true 6 feet if you hang pickets 2 inches up and trim posts to match.
• 8 foot fence: 8 foot pickets, often used in rural areas or for sound and wind screening where local rules allow. Expect extra weight and the need for a third or fourth rail.

Check height rules before buying. Many municipalities limit residential fences to 6 feet in rear yards and 3 to 4 feet in front yards, measured from grade.

Tools and Materials

• Pickets, 2×4 rails and 4×4 posts in matching species (pressure-treated pine, cedar or redwood)
• Pneumatic fence nailer or a framing nailer that accepts ring-shank nails
• Hot-dipped galvanized or stainless ring-shank nails, or exterior screws
• Picket spacer (a scrap block cut to your gap width)
• Tape measure, speed square, 4 foot level and mason’s line
• Circular saw and miter saw for trimming
• Safety glasses, hearing protection and work gloves

A pneumatic fence nailer speeds the job dramatically. A typical 8 foot privacy section takes around 17 pickets and two or three nails per picket per rail, so a 100 foot fence can mean well over 1,500 nails. Driving those by hand is slow and tends to split thin 5/8 inch boards.

Worked Example: Counting Boards per Section

Here is how to count boards for one 8 foot section, then scale to a full fence. Assume posts are 8 feet on center, 4×4 posts (3.5 inches wide), and pickets face-mounted on the rails so they run continuously past the posts.

Option 1: Side-by-side with small gaps

1. Section width center to center: 96 inches.
2. Picket width: 5.5 inches. Gap: 1/4 inch for drainage and swelling. Each picket plus gap occupies 5.75 inches.
3. Pickets per section: 96 divided by 5.75 equals 16.7. Round up to 17.
4. For a 100 foot run with 12.5 sections: 12.5 times 16.7 equals about 209 pickets. Add 5 to 10 percent for culls and cuts: buy about 225.

Option 2: Tight privacy, no gaps

Butting boards edge to edge, 96 divided by 5.5 equals 17.5 pickets per section, so plan on 18. Be aware that green pressure-treated boards shrink as they dry, often opening 1/8 to 1/4 inch gaps on their own within a season. Kiln-dried boards butted tight can swell and buckle, so a small gap is usually smarter.

Option 3: Board-on-board (shadowbox overlap)

Board-on-board uses two layers. The back layer is spaced with gaps, and the front layer covers each gap with an overlap of about 1 to 1.5 inches on each side.

1. Using 5.5 inch boards and a 1 inch overlap per side, set back-layer boards with a 3.5 inch gap (5.5 minus 2).
2. Each back board plus gap takes 9 inches. Back layer: 96 divided by 9 equals 10.7, so 11 boards.
3. Front layer covers each gap: about 10 to 11 boards.
4. Total per section: roughly 22 boards, versus 17 for a single layer. That is about 30 percent more lumber for full privacy from both sides.

Rails and posts

Each 8 foot section needs two rails for a 4 foot fence and three for a 6 foot fence. Use 8 foot 2x4s for face-mounted rails or 16 foot boards spanning two sections where you want fewer joints. Posts equal the number of sections plus one, plus extras for corners and gates.

Installation Tips for Clean, Even Spacing

1. Stretch a string line along the bottom where pickets should end, about 2 inches above the soil.
2. Plumb the first picket with a level and fasten it. Every board after takes its alignment from this one.
3. Use a spacer block for consistent gaps rather than eyeballing.
4. Every 4 or 5 boards, check for plumb and adjust the gap slightly to correct drift.
5. When nearing a post or corner, measure the remaining distance and divide it so the last few gaps are equal, rather than ending on a sliver.
6. Fasten with two nails per rail per picket, placed about 3/4 inch from each edge to reduce splitting.

Troubleshooting Board Problems

• Boards cup or twist: Usually caused by thin or wet boards drying unevenly. Use thicker stock, fasten at each rail, and seal both faces.
• Splitting at nails: Move nails in from the board ends, use blunt-tip or ring-shank nails, or pre-drill near the edges.
• Gaps opening over time: Normal shrinkage of green lumber. Board-on-board hides it.
• Bottom rot: Boards touching soil. Maintain 2 inches of clearance or add a pressure-treated rot board along the bottom.
• Wavy top line: Pickets were set to follow the ground. Use a string line at the top or trim tops after installation with a circular saw guided by a straightedge.

Cost Ranges

Once you know your fence board dimensions and count, pricing the job is straightforward. Pressure-treated pine pickets are the budget option, often costing a few dollars apiece for a 6 foot dog-ear. Cedar pickets typically run around one and a half to two times that price, and redwood or premium clear grades cost more. Board-on-board designs add roughly 30 percent in lumber. Fasteners, rails, posts and concrete add to the total, and professional labor generally doubles the project cost compared with doing it yourself.

When to Call a Pro

Building a fence board by board is a reasonable DIY project for anyone comfortable with a saw and a nailer. Consider hiring a fence contractor if you need posts set on a steep grade, in rocky soil, or along an unclear property line, or if your local permit requires a professional plan. A pro crew can also be worth it for long runs where speed and straight lines matter most.