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Fence Calculator
Fence Calculator
Project Calculators

Fence Calculator

Calculate fence posts, pickets, rails, and total material cost.

DIY difficulty

ModerateTypical time: 1–2 weekends
  • ›Post holes must be dug below frost line and set in concrete
  • ›Keeping posts plumb and in line requires patience
  • ›Call 811 before digging to check for underground utilities

Must-have tools

Post hole digger or augerLevelString lineDrill or nail gun

How to calculate fence materials

  1. Enter the total fence run in feet. Walk the perimeter or measure on a plot plan — include all sides.

  2. Set your post spacing. Eight feet on center is standard for most privacy fences; 6 feet works better for tall or heavy styles.

  3. Enter picket width and gap. A 3.5-inch picket with a 0.5-inch gap is common for a standard privacy look.

  4. Add gates and enter per-item prices to get a complete material cost estimate.

Common uses

  • Planning a backyard privacy fence or dog run
  • Estimating materials for a ranch or split-rail fence
  • Getting a materials list before pulling a permit

Frequently asked questions

How many fence posts do I need for 100 feet of fence?
At 8-foot spacing, 100 feet needs 13 posts (100 ÷ 8 = 12.5, rounded up to 13, plus one end post). Always add 1 to the section count.
How deep should fence posts be set?
A general rule is one-third of the total post length in the ground. A 6-foot-tall fence needs posts set at least 2 feet deep, or deeper in frost-prone areas.
How many rails does a standard fence need?
Most fences up to 6 feet tall use 2 horizontal rails — one near the top, one near the bottom. Taller fences and those in high-wind zones benefit from a third middle rail.
How much concrete do I need per fence post?
Use 2 bags of 60 lb concrete per post for a standard 4×4 post in a 10-inch hole at 2 feet deep. Mix the concrete dry in the hole and add water — the "dry set" method works well for fence posts.
How deep should fence posts be for a 6-foot fence?
Set posts at least 2 feet deep — one-third of the total post length. In frost-prone climates, go below the local frost line (often 3–4 feet deep) to prevent heave.

Common mistakes to avoid

  • ✕Not calling 811 before digging — call at least 3 business days before any post hole. Hitting a buried line is a serious safety and legal issue.
  • ✕Setting posts before confirming the property line — installing over the line requires removal at your expense.
  • ✕Insufficient post depth in frost climates — posts must go below local frost depth, not just follow the one-third rule.
  • ✕Using above-ground rated lumber for posts — posts set in soil require UC4B (ground contact) rated lumber, not standard pressure-treated.

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Not sure whether to DIY this project?

Read our project-by-project guide on when to hire a contractor vs. do it yourself.

Read the guide →

About this calculator

Enter your total fence length, post spacing, picket width, and gap to get exact counts for posts, pickets, and rails. Add optional gate count and per-item pricing for a cost estimate.

All results are estimates. Verify quantities with your local supplier and confirm measurements before purchasing materials. Requirements vary by region and project type.

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