Fence Picket Calculator: How Many Pickets (and Posts) Do You Need?

A fence project lives or dies at the lumber yard. Buy too few pickets and you're making a second trip (and praying the new batch matches). Buy too many and you've got $200 of lumber leaning against your garage for the next three years. Here's how to get it right the first time.

Step 1: Measure your total fence run

Walk the fence line with a tape measure (or a measuring wheel) and get the total linear feet. Don't try to be clever and subtract the gate yet — we'll handle that in a moment. Just the full run.

Example: 100 ft of backyard fence.

Gates: measure each gate opening and subtract it from the total run for pickets — but remember the gate still needs its posts. A 4 ft gate in a 100 ft run = 96 ft of pickets, but posts for the full layout.

Step 2: Calculate pickets

This is the number everyone gets wrong. The formula:

Pickets = Total inches ÷ (picket width + gap)

Convert feet to inches first (100 ft = 1,200 in). A standard 1×6 picket is actually 5.5 inches wide:

• Privacy fence (no gap): 1,200 ÷ 5.5 = 219 pickets
• Spaced picket (2" gap): 1,200 ÷ 7.5 = 160 pickets

Always round up — and then add 5–10% extra for miscuts, warped boards, and the one picket you'll inevitably drop in the mud. For our 100 ft privacy fence: 219 × 1.1 ≈ 241 pickets.

Step 3: Calculate posts

Posts go at regular intervals — 8 ft apart is standard for wood fences (6 ft for heavy or high-wind areas).

Posts = (Total feet ÷ spacing) + 1

The +1 is the part people forget: a 100 ft run with 8 ft spacing has 12.5 → 13 sections, which means 14 posts (one at each end of every section).

Add 2 extra posts per gate (gate posts should be beefier — use 6×6 instead of 4×4 for gates).

Step 4: Calculate rails

Rails are the horizontal 2×4s the pickets screw into. Most fences use 2 rails per section (3 for fences over 6 ft tall or for extra rigidity).

Rails = Sections × rails per section

Our example: 13 sections × 2 rails = 26 rails (buy 8-ft 2×4s).

Step 5: Don't forget the concrete

Every post needs concrete — roughly one 50-lb bag per post for a standard 2 ft deep hole. Our 14-post fence = 14 bags. In cold climates, set posts below the frost line (often 3 ft+ deep) — which means more concrete per hole.

Your shopping list (100 ft privacy fence example)

| Material | Quantity | |---|---| | 1×6 pickets (5.5" wide) | ~241 (with 10% extra) | | 4×4 posts | 14 | | 2×4 × 8 ft rails | 26 | | 50-lb concrete bags | 14 | | Exterior screws (2.5") | ~5 lbs |

Pro tips from people who've built too many fences

• Buy pickets from the same batch. Wood varies — different batches can be visibly different shades, even "the same" product.
• Let pressure-treated lumber dry 2–4 weeks before staining, or the stain won't take evenly.
• Call 811 before you dig. In the US, it's free, it's the law in most states, and hitting a gas line ruins your whole week.
• Crown your pickets: the slight arch on top of each picket should face outward — it sheds water instead of pooling it.

Skip the arithmetic — our free fence calculator does pickets, posts, rails, and concrete instantly. Enter your fence length and it builds the whole shopping list.