Fence Calculator

Work out how many posts, rails and pickets you need for a wood or picket fence from its length, post spacing and board size, with extra pickets for waste and an optional materials cost. Your inputs stay in your browser.

Your fence

The fence line

Add up every side you are fencing.

8 feet is common for wood fences; 6 feet for heavier or taller fences.

Often 2 for a fence up to 4 feet and 3 for a 6-foot fence.

The pickets

Actual width: a nominal 1 × 6 board is about 5.5 inches.

Enter 0 for boards butted together.

For split or warped boards; 5% is typical.

Cost (optional)

330 pickets, 20 posts and 57 rails. See full results

Example: 150 ft of fence with posts every 8 ft, 3 rails per section, and 5.5-inch pickets with a 0.25-inch gap and 5% extra. Enter your numbers to update.

Your fence materials

Pickets
330
314 to cover the line, plus 5% extra
Posts
20
19 sections of 7.89 ft
Rails
57
3 per section

Materials list

ItemQuantityCost
Posts 20—
Rails 57—
Pickets 330—

Add prices to estimate the cost of materials.

Gates, post caps, concrete, fasteners and hardware are not included.

How to calculate fence materials

  1. Sections: divide the length by the post spacing and round up: 150 ÷ 8 → 19 sections of 7.89 feet.
  2. Posts: one more than the number of sections, because each end needs a post: 20 posts for a single straight run.
  3. Rails: sections × rails per section: 19 × 3 = 57 rails, each as long as a section.
  4. Pickets: convert the length to inches (1 foot = 12 inches; NIST: tables of units of measurement). With a gap between boards, n pickets cover n × width + (n − 1) × gap, so you need (length + gap) ÷ (width + gap), rounded up: 314 pickets, or 330 with 5% extra.

Post spacing and picket layout

Closer posts make a stiffer fence but cost more: at 6-foot spacing, the example needs 26 posts instead of 20. For a spaced picket fence with 3.5-inch pickets and 3.5-inch gaps and two rails, it takes 271 pickets. Local rules can limit fence height or placement near property lines, and in many places you must call 811 before digging post holes.

What this calculator does not include

  • Gates and their posts and hardware. Leave the gate width out of the length and add gates separately.
  • Corners and separate runs: each separate straight run needs its own end posts, so work out each run separately.
  • Concrete or gravel for post holes, post caps, screws or nails, stain and labor.

Results are estimates for planning a purchase.

Methodology and testing

Automated tests compare sections, posts, rails and pickets with an independent calculation, check the picket count against a board-by-board count, and check that a length that is an exact number of sections does not get an extra post. How we build and test calculators.

Sources

  • Board Foot Calculator

    Board feet for up to four stacks of lumber, quarter-size thickness, waste allowance and cost per board foot.

  • Deck Calculator

    Deck boards, joists and screws from deck size, board size, gap and joist spacing, with waste and cost.

  • Home Equity Loan Calculator

    Monthly payment, borrowing limit at common CLTV caps, cash received after closing costs, term comparison and amortization.