Wood Picket Calculator: Fence Board Count

This wood picket calculator works out how many pickets (fence boards) you need for a straight fence run, and the total board footage. You enter the total fence length, the picket width, and the gap between pickets, and it returns the number of pickets required plus the total linear feet of lumber.

Formula

The number of pickets is found by dividing the total fence length (converted to inches) by the sum of one picket width plus one gap. The formula is:

N = ceil( L × 12 / (W + G) )

• L = total fence length in feet (e.g., 100 ft)
• W = picket width in inches (e.g., 5.5 in for a standard 1×6 board)
• G = gap between pickets in inches (e.g., 0.5 in)
• N = number of pickets (always rounded up to a whole board)

The total lumber length in feet is then N × W / 12, because each picket’s width (in inches) is converted to feet.

Worked Example

Using the default values: fence length = 100 ft, picket width = 5.5 in, gap = 0.5 in.

1. Convert fence length to inches: 100 ft × 12 = 1200 in
2. Add picket width and gap: 5.5 + 0.5 = 6.0 in per picket+gap unit
3. Divide: 1200 ÷ 6.0 = 200 pickets exactly
4. Total lumber: 200 × 5.5 = 1100 in ÷ 12 = 91.67 ft

The calculator returns 200 boards and 91.67 ft of picket lumber. Note that this is the picket material only – it does not include horizontal rails, posts, or waste.

When to Use This Calculator

Use this tool when you are planning a new wood fence, replacing individual pickets, or estimating material for a quote. It works for any straight fence run where pickets are evenly spaced with a consistent gap. Common uses include:

• Estimating how many 1×4, 1×6, or dog-eared pickets to buy
• Planning a privacy fence (gap = 0) or a semi-private fence with a 1–2 inch gap
• Calculating material for a garden border or screen

The calculator assumes the pickets are installed vertically and that the gap is uniform. If you plan to overlap pickets (board-on-board), set the gap to a negative value equal to the overlap in inches – but be aware that some lumber yards sell pickets with rounded edges, so measure the actual face width.

How to Choose Picket Width and Gap

The two numbers you enter have a big effect on the count. Here are typical values:

• Picket width: A standard 1×6 board is 5.5 in wide (the nominal 6 in is before planing). A 1×4 is 3.5 in. Dog-eared pickets are often 5.5 in wide.
• Gap: For a privacy fence, gap = 0. For a “good neighbor” fence with spacing, gaps of 0.5 to 1 in are common. Larger gaps (2–3 in) are used for decorative fences.

If you are mixing picket widths (e.g., alternating 4-in and 6-in boards), calculate each section separately or use an average width. For a board-on-board fence, the overlap is typically 1–2 in, so you would enter a negative gap (e.g., -1) to get the correct count.

Common Mistakes and How to Avoid Them

Several errors can throw off your estimate:

• Using nominal instead of actual width: A “1×6” is actually 5.5 in wide. If you enter 6, you will underestimate the number of pickets.
• Forgetting to convert units: The formula works in inches. If you enter the fence length in feet and the width in inches without converting, the result will be wrong.
• Rounding down: Always round up to the next whole picket. You cannot buy half a board, and cutting a board to fit leaves waste.
• Ignoring waste: The calculator gives the theoretical minimum. Add 5–10% for cuts, damaged boards, and mistakes. For a 100-ft fence, that means buying 210–220 pickets instead of 200.

Also remember that the calculator only counts pickets. You still need horizontal rails (usually 2×4s) and posts (4×4s) every 6–8 ft, plus concrete, nails or screws, and post caps.

Limits of the Formula

This formula assumes a perfectly straight fence line with no corners, gates, or posts that interrupt the picket spacing. In reality, you will need to adjust the spacing at the ends to avoid a gap wider than the others. The formula also does not account for:

• Pickets that are cut at an angle (e.g., scalloped tops) – the width is still the same, but you may need extra for waste.
• Pickets that are installed on a slope – the horizontal distance is what matters, not the ground distance.
• Gates – you will need to skip pickets or use different widths at the gate opening.

For a curved or angled fence, break the run into straight segments and calculate each separately. For a very long fence, the calculator gives a good estimate, but always lay out the first few sections on site to confirm the spacing looks right.

Frequently Asked Questions

How many pickets do I need for a 100-foot fence?

With 5.5-in wide pickets and a 0.5-in gap, you need 200 pickets (as in the example). If you use a 3.5-in wide picket with the same gap, you need 300 pickets. The exact number depends on the width and gap you choose.

What is the standard gap between fence pickets?

There is no universal standard. For privacy, the gap is 0 (boards touching). For a semi-private fence, 0.5 to 1 inch is common. For a decorative fence, gaps of 2 to 3 inches are typical. Building codes in some areas may limit gap size for pool safety, so check local rules.

How much wood do I need for a picket fence?

Besides the pickets, you need horizontal rails (usually 2×4s) and posts (4×4s). For a 100-ft fence with posts every 8 ft, you need about 13 posts and 200 ft of rail (two rails per section). The picket lumber itself is about 92 ft for 5.5-in boards with a 0.5-in gap, as shown above.

Should I add extra pickets for waste?

Yes. Add 5–10% to the calculated number to cover cuts, damaged boards, and mistakes. For a 200-picket fence, that means buying 210–220 pickets. It is cheaper to have a few extra than to make a second trip to the store.

Can I use this calculator for a board-on-board fence?

Yes, but enter a negative gap equal to the overlap. For example, if you overlap 1 inch, set the gap to -1. The formula will then give the correct number of pickets. Note that board-on-board fences use about twice as much lumber as a single-layer fence.

What if my fence is not straight?

Break the fence into straight segments and calculate each one separately. For a curved fence, you will need to cut pickets at an angle or use flexible materials; this calculator is only accurate for straight runs.

Related

• Pocket Calculator Argos: What It Is & How to Use
• Pocket Calculator Casio: How to Pick and Use One
• Pocket Calculator Font: What It Is & How to Get It

in len | Fence length | ft | 100 | 0
in pw | Picket width | in | 5.5 | 0
in gap | Gap between pickets | in | 0.5 | 0
out count | Number of pickets | boards | ceil(len * 12 / (pw + gap)) | 0
out total_ft | Total picket lumber | ft | (ceil(len * 12 / (pw + gap)) * pw) / 12 | 2