CalculatorAsphalt

Fence Calculator

Posts, rails, pickets and concrete bags for a wood fence run.

Quick answer: Posts on 8 ft centers = length ÷ 8 + 1. Rails: 2 per section under 6 ft tall, 3 for 6 ft+. Pickets = run in inches ÷ picket width. Each post sets in two 50 lb concrete bags.

How to use this calculator

  1. Enter Fence length in ft.
  2. Enter Height in ft.
  3. Enter Gates.
  4. Press Calculate. The highlighted row is your order quantity; the note beneath it translates the number into real-world terms.

Formula & constants

Posts on 8 ft centers = length ÷ 8 + 1. Rails: 2 per section under 6 ft tall, 3 for 6 ft+. Pickets = run in inches ÷ picket width. Each post sets in two 50 lb concrete bags. Every default in the fields above is editable — when your supplier’s spec sheet lists a different density, coverage rate or price, enter that number instead. The waste and compaction allowances follow common trade practice; see our methodology page for the derivation of each formula and the standards it references.

Worked example. With fence length = 10 ft, height = 6 ft, gates = 1, the calculator returns:
Posts4 posts
Rails (8 ft)6 rails
Pickets (5.5 in)22 pickets
Concrete bags8 bags

Where this fits in the project

Fence runs are linear takeoffs: posts on 8 ft centers, two or three rails per section, then infill. Every post needs a hole below frost line — check the post depth calculator — and about two bags from the concrete bag calculator to set it.

How this connects to your project

No quantity stands alone — each material in the chain depends on the ones around it. These are the planning steps that pair with the fence calculator:

Frequently asked questions

How many posts for 100 ft of fence?

14 line posts at 8 ft spacing plus extra posts at each gate — gates hang on their own reinforced posts.

Should fence posts be 8 ft apart?

8 ft max for wood; 6 ft in high-wind zones or for heavy solid-board designs.

Last verified: — prices reflect current national averages. See our methodology.

Estimates are for planning. Material densities, coverage rates and prices vary by region and supplier — confirm final quantities before ordering, and check local code where structural or electrical work is involved.