ProjectCalcBUILT FOR THE JOB.

Fence & posts

Fence Calculator

Estimate the posts, rails and vertical pickets for a connected wood fence. Enter each straight run separately so corner posts and partial bays are counted correctly.

Imperial + metricFraction-friendly inputsFree · No loginSee the math ↓

Project measurements

01 / INPUTS

Mix units freely: 8 ft, 100 mm, or 5' 7 1/2". Unmarked dimensions use the selected unit.

View live estimate ↓
Separate each straight run with a comma. Example: 40, 60. Bare numbers use the selected unit.
Applied before rounding purchase quantities.

Your estimate

LIVE RESULT
Pickets to purchase
241pickets
Includes your selected allowance
Total fence length100 ft
Fence bays13 bays
Pickets before waste219 pickets
Total fence length (metric)30.48 m

Purchase / material list

Setting posts14 posts
Rail pieces before waste39 pieces
Rail pieces to purchase43 pieces

No account. Calculations stay in your browser.

Before you order

  • Connected, uninterrupted runs share corner posts. Open runs have two ends; a closed perimeter shares the last post.
  • Picket coverage uses full run length, without subtracting posts. Face-mounted vertical pickets only; no gates, panels, overlaps or slope allowance.
  • One rail piece spans one bay. Select stock long enough for each bay and its connections. Posts have no waste allowance.

UNDERSTAND YOUR ESTIMATE

How to use the fence calculator

Measure along the fence line and split it at every corner. Each run gets its own whole number of bays; spacing can be reduced to make those bays equal. Pickets are calculated by coverage across each run, while rails are counted as individual pieces spanning bays. This produces a material takeoff for a face-mounted picket fence.

Formula

Bays = Σ ceil(run length ÷ maximum spacing)
Posts = bays + 1 (open), or bays (closed)
Pickets = Σ ceil((run length + gap) ÷ (picket width + gap))
Purchase pickets = ceil(pickets × (1 + waste ÷ 100))

Assumptions & scope

  • Runs are connected end to end and share corner posts. For disconnected stretches, calculate each stretch separately.
  • Gate openings are excluded. Calculate the uninterrupted sections on either side separately and add gate hardware and supporting posts according to the gate design.
  • Pickets do not overlap and are not installed board-on-board. Actual lumber width is used, not the nominal trade size.
  • Post spacing, rail count and fence height must suit the approved construction detail; this tool does not size structural members.
ON THE JOB / WORKED EXAMPLE

A calculation you can check

For one 100 ft run with 8 ft maximum spacing, 5½ in pickets, no gaps, three rails per bay and 10% waste: 13 bays, 14 posts, 219 net pickets and 241 purchase pickets. Rails are 39 net pieces or 43 with allowance.

Quick reference

Fence Calculator reference values
Run lengthBays at 8 ft maxPosts, open run
50 ft78
100 ft1314
150 ft1920
200 ft2526

Calculation methodology

Run-by-run spacing and picket coverage are evaluated at full precision, with whole-piece rounding only at bay, picket and purchase boundaries.

Length conversions use the NIST SI conversion factors. See our calculation and editorial standards for precision, validation and limitations.

Common questions

Should I enter nominal or actual picket width?

Use the measured coverage width. A nominal 1×6 picket may measure 5½ inches, but products vary; measure the actual stock before ordering.

How do I handle corners and gates?

Enter connected straight runs separated by commas. Corners share one post. Gates interrupt the coverage calculation, so calculate the separate fence sections and plan gate posts and hardware independently.

Does waste increase my post count?

No. Posts are counted from the layout. Waste increases pickets and rails, with rounding applied after the allowance. Add spare posts manually if required.