BYTETOOLS

Fence Calculator

Turn a fence run and post spacing into post, rail, picket and panel counts, with gate openings deducted and the concrete needed for every post hole.

96.00
Fence run after gates (ft)
12
Sections / bays
15
Posts
220
Pickets
36
Rails
288.0
Rail material (ft)
0.92
Concrete per hole (ft³)
24 × 80 lb
Concrete bags

Sections = run ÷ post spacing rounded up; posts = sections + 1, plus two posts per gate opening. Pickets are spaced on a pitch of picket width + gap, with a 5% allowance. Post-hole concrete is π r² × depth minus the post itself — that usually works out at one to two 80 lb bags per hole. Corners, slopes and stepped runs need extra posts. Check local rules on fence height and boundary position before you build. Estimates only.

What is the Fence Calculator?

The ByteTools Fence Calculator builds a materials list for a fence. Enter the total run and your post spacing, deduct gate openings, and it works out the number of sections, posts, rails and either pickets or pre-made panels — plus the volume of concrete each post hole takes and how many bags that is.

  • Post, rail, picket and panel counts from one run length
  • Gate openings deducted with a pair of posts added each
  • Picket spacing set by board width plus gap
  • Post-hole concrete volume and bag count
  • Adjustable picket waste allowance, 5% by default
  • Imperial and metric, all calculated in your browser

How to use the Fence Calculator

  1. 1

    Choose imperial or metric and pick a picket fence or pre-made panels.

  2. 2

    Enter the total fence run, your post spacing, and how many gates and how wide.

  3. 3

    Set the rails per section, and the picket width and gap for a board fence.

  4. 4

    Enter the post width, hole diameter and hole depth for the concrete estimate.

  5. 5

    Read the post, rail, picket and concrete bag counts.

About the Fence Calculator

The ByteTools Fence Calculator builds a materials list for a fence. Enter the total run and your post spacing, deduct gate openings, and it works out the number of sections, posts, rails and either pickets or pre-made panels — plus the volume of concrete each post hole takes and how many bags that is.

Picket counts are worked out on the pitch of picket width plus gap, so a solid privacy fence and a spaced picket fence give properly different numbers. A small waste allowance covers split and bowed boards. Post-hole concrete is π r² times depth with the post itself subtracted.

Everything is calculated in your browser and nothing is uploaded. Corners, slopes, stepped runs and end posts all need extra material, and fence height and boundary position are often regulated locally, so check the rules and confirm the boundary line before you build. Estimates only, not a substitute for a fencing contractor's quote.

Frequently asked questions

How far apart should fence posts be?

Six to eight feet (1.8 to 2.4 m) is standard for a timber fence. Closer spacing makes a stiffer fence and is worth it in exposed, windy positions or with heavy solid panels; wider spacing lets rails sag over time.

How many pickets do I need for 100 feet of fence?

Divide the run in inches by the picket width plus gap. A hundred feet is 1,200 inches, so 5½-inch boards butted together need 219 pickets, or 230 once the 5% waste allowance is added. Leaving a half-inch gap between boards brings that down to 210.

How much concrete does a fence post need?

A 10-inch-wide hole 24 inches deep holds about 0.9 cubic feet once the post is deducted, which is one and a half 80 lb bags. The rule of thumb of one to two bags per post holds for most residential fences. Dig the hole about three times the post width.

How deep should fence post holes be?

At least one third of the post's total length, and always below the local frost line where the ground freezes. Deeper posts resist wind loading and frost heave far better, and a gravel layer at the bottom helps the post drain rather than rot.

Does this include corner and end posts?

The count is sections plus one, which covers a single straight run with an end post at each end, plus two posts per gate opening. Every corner, direction change and stepped section on a slope needs an additional post, so add those manually.

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