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FigureWright

Fence Picket Calculator

Work out how many pickets to buy and the exact gap that spaces them evenly along your fence.

Your fence

Units

The length the pickets need to cover. Leave gate openings out.

Measure the face: a 1×4 is 3½ in, a 1×6 is 5½ in.Measure the face width of one picket.

Use 0 for a privacy fence with pickets butted together.

sections

Leave at 0 for one continuous run. Enter a number if pickets restart at every post.

Extra boards for cuts, splits and defects. 5–15% is common.

Results update as you type. Fractions like 5 1/2 work too.

FigureWright:

Your estimate

Imperial unitsMetric units
Pickets to buy
222
incl. 10% waste
Before waste
201
Extra for waste
+21
Even gap
2.48 in
to fit the length exactly

Layout

Layout
One continuous run
Pickets per foot
2.01
Face covered by pickets
59%

Spacing

Gap you entered
2.5 in
Even gap to fill the length exactlySpreads 201 pickets evenly edge to edge.
2.483 in (≈ 2½ in)
If you keep your gap exactlyThe last picket runs past the end. Trim it, or use the even gap.
3.5 in over
  • Pickets are rounded up to whole pieces, then the waste allowance is added and rounded up again.
  • Because of that rounding, the gap usually needs to shrink slightly to fit. Use the even gap figure.

A planning estimate, not a contractor quote. Fence rules, permitted heights, post depth and setbacks vary by location. Check with your local building authority before you build.

The picket formula

pickets = ⌈ (fence length + gap) ÷ (picket width + gap) ⌉

Every picket takes up its own width plus one gap. A row of n pickets has only n − 1 gaps, though, so one gap is added to the length before dividing. The result is rounded up to a whole picket. With no gap, it simplifies to fence length ÷ picket width.

The waste allowance is then added and rounded up again:

pickets to buy = ⌈ pickets × (1 + waste % ÷ 100) ⌉

Getting the spacing right

Rounding up means your pickets won’t land exactly on the end of the fence with the gap you chose. There are two fixes: trim the last picket, or shrink every gap slightly so the pickets fit exactly. The calculator gives you that exact figure:

even gap = (length − pickets × picket width) ÷ (pickets − 1)

A simple spacer block cut to the even gap makes installation quick and consistent. Check your spacing every few feet so small errors don’t add up.

Worked example

A 100 ft picket fence with 3½ in pickets and a 2½ in gap, plus 10% waste:

  1. Convert to inches: 100 ft = 1,200 in.
  2. (1,200 + 2.5) ÷ (3.5 + 2.5) = 1,202.5 ÷ 6 = 200.4 → 201 pickets.
  3. Waste: 201 × 1.10 = 221.1 → 222 pickets to buy.
  4. Even gap: (1,200 − 201 × 3.5) ÷ 200 = 496.5 ÷ 200 = 2.48 in, just under the 2½ in you planned.

The same example in metric: 30 m of fence with 9 cm pickets and 6 cm gaps needs (30 + 0.06) ÷ 0.15 = 200.4 → 201 pickets.

Measuring picket width

Use the actual width, not the nominal size. A “1×4” picket is about 3½ in wide and a “1×6” about 5½ in. Dog-ear and French-gothic tops don’t change the count. Only the face width and gap matter.

Frequently asked questions

How many pickets do I need per foot?

Divide 12 in by the picket width plus the gap. With 3½ in pickets and 2½ in gaps that is 12 ÷ 6 = 2 pickets per foot. A privacy fence of 5½ in pickets with no gaps needs about 2.2 per foot.

How wide should the gap between pickets be?

It’s a design choice. Traditional picket fences often leave a gap somewhere between half and the full width of a picket. Privacy fences butt the pickets together or leave only a small gap for swelling.

What is the even gap?

Because you can’t buy part of a picket, the count is rounded up, so with your exact gap the last picket won’t finish flush with the end. The even gap is the spacing that fits your whole number of pickets exactly edge to edge. It’s usually a fraction smaller than the gap you entered.

Should I count gates?

Leave gate openings out of the length. If your gates are made from matching pickets, calculate each gate separately using its width as the length.

When should I enter a number of sections?

When the pickets stop and restart at every post, for example when they sit between posts rather than running across them. Each section is then counted and rounded up on its own, which can add a few pickets.

Related calculators

How these numbers are worked out, and their limits, is explained on the methodology page.