Fence Calculator

The fence calculator is a construction planning tool that estimates the number of posts, rails, and pickets required for a fence, along with the concrete volume needed for post footings. Enter your fence length, post spacing, and picket dimensions — and the calculator returns all material counts instantly.

What Is a Fence Calculator?

A fence calculator is a practical tool that helps you plan and estimate all the materials needed to build a fence. It breaks the fence down into its core components — posts, rails, and pickets — and calculates how many of each you need based on your dimensions. It also estimates the concrete volume required to set each post securely in the ground, so you can budget and order all materials in one go.

How the Fence Calculator Works

Posts Section

• Fence length — total length of the fence run (unit: meters)

• Post space — distance between posts, default: 2.5 m

• Number of posts — auto-calculated from fence length and post spacing

• Number of sections — auto-calculated (sections = spaces between posts)

• Fence height — height of the fence (unit: meters)

• Post length — auto-calculated based on fence height and footing depth

Rails Section

• Rails per section — default: 2 rails per section

• Number of rails — auto-calculated from sections × rails per section

Pickets Section

• Picket width — width of each picket board (unit: cm)

• Picket spacing — gap between each picket (unit: cm)

• Number of pickets — auto-calculated from fence length, picket width, and spacing

Concrete for Post Footing

• Post shape — select Cuboid (default) or Cylindrical

• Post width — width of the post (unit: cm)

• Post thickness — thickness of the post (unit: cm)

• Concrete volume — auto-calculated total volume needed (m³)

The calculator also suggests visiting the cement calculator to determine how much cement, sand, gravel, and water you'll need for the concrete volume.

The Fence Calculation Formulas

Number of posts: (Fence Length ÷ Post Space) + 1 = Number of Posts

Number of sections: Number of Posts − 1 = Number of Sections

Number of rails: Number of Sections × Rails per Section = Number of Rails

Number of pickets: Fence Length ÷ (Picket Width + Picket Spacing) = Number of Pickets

Concrete volume (cuboid post footing): Post Width × Post Thickness × Footing Depth = Concrete Volume per Post Total Concrete Volume = Concrete Volume per Post × Number of Posts

How to Calculate Fence Materials — Step by Step

Example 1: Basic Garden Fence

Fence length = 20 m, Post space = 2.5 m, Rails per section = 2.

Step 1: Posts — (20 ÷ 2.5) + 1 = 9 posts. Step 2: Sections — 9 − 1 = 8 sections. Step 3: Rails — 8 × 2 = 16 rails.

Enter: Fence length = 20, Post space = 2.5, Rails per section = 2. Results: 9 posts, 8 sections, 16 rails.

Example 2: Adding Pickets

Same fence, Picket width = 10 cm, Picket spacing = 2 cm.

Step 1: Convert fence length — 20 m = 2,000 cm. Step 2: Pickets — 2,000 ÷ (10 + 2) = 2,000 ÷ 12 = 166 pickets.

Enter picket width = 10 cm and spacing = 2 cm. Result: 166 pickets.

Fence Materials Reference Table

Note: Values use default post spacing of 2.5 m and 2 rails per section. Adjust inputs for different spacing requirements.

Frequently Asked Questions

How many fence posts do I need for 100 feet?

100 feet is approximately 30.5 m. At the default post spacing of 2.5 m, you need (30.5 ÷ 2.5) + 1 = roughly 13 posts. Enter your exact fence length in meters into the fence calculator to get a precise post count for your specific spacing.

How do I calculate the number of pickets needed?

Divide your total fence length (in cm) by the sum of picket width and picket spacing. For example, a 20 m fence with 10 cm wide pickets and 2 cm spacing needs 2,000 ÷ 12 = 166 pickets. Enter your picket width and spacing into the calculator and it computes this automatically.

What is post spacing in a fence calculator?

Post spacing is the distance between the centers of two adjacent fence posts. The default in this calculator is 2.5 m. Closer spacing means more posts and a stronger fence; wider spacing uses fewer posts but may require thicker rails for structural support.

What is concrete for post footing used for?

Post footings are the underground concrete bases that anchor fence posts into the ground. The calculator estimates the concrete volume needed based on your post dimensions and shape — either cuboid or cylindrical. This ensures your posts stay upright and stable over time.