Board-on-Board Fence Calculator

What This Calculator Does

This calculator estimates the lumber and hardware needed for a board-on-board privacy fence. It accounts for boards, posts, rails, and fasteners based on your fence dimensions and material spacing preferences.

Board-on-board fencing uses overlapping vertical pickets to eliminate gaps, providing full privacy from both sides. Unlike standard picket fences, the overlapping design requires roughly twice the number of boards per linear foot.

How the Calculation Works

The calculator uses your fence length, height, and board dimensions to determine material quantities. Key calculations include:

• Total boards – based on fence length divided by the exposed face width of each board, then doubled for the overlapping layers
• Posts – spaced at your specified interval (typically 6–8 feet), with an extra post for each corner or gate opening
• Rails – two or three horizontal runs per section, depending on fence height
• Fasteners – estimated per board attachment point, with a waste factor included

All estimates assume standard lumber dimensions and typical construction practices. Adjustments for gates, slopes, or irregular terrain are not included.

How to Use the Calculator

1. Enter the total fence length in feet.
2. Enter the fence height in feet.
3. Select your board width and desired gap (if any) between overlapping boards.
4. Choose post spacing and number of rails per section.
5. Click calculate to see estimated quantities for boards, posts, rails, and fasteners.

Review the results and add 5–10% for waste, cuts, and mistakes.

Understanding Your Results

The output shows individual material counts, not bundled packages. Use these numbers to create your lumber list for a supplier.

• Board count – includes both front and back layers. If you want a staggered appearance, order equal quantities for each side.
• Post count – includes corner and end posts. Gate posts are not automatically added; add two extra posts per gate opening.
• Rail length – assumes standard 8-foot or 12-foot lumber. You may need to cut rails to fit between posts.
• Fastener estimate – based on two fasteners per board per rail. Actual count varies with rail configuration.

Common Mistakes to Avoid

• Forgetting the overlap factor – board-on-board requires double the boards of a standard fence. Underestimating this is the most common error.
• Ignoring post depth – posts should be set one-third of their length into the ground. A 6-foot fence needs 8-foot posts minimum.
• Not accounting for gates – gate openings remove fence sections and require additional hardware. Adjust your total length accordingly.
• Assuming perfect spacing – lumber varies in width. Dry or wet conditions can cause boards to shrink or swell, affecting fit.

Practical Use Cases

• Residential privacy fencing – board-on-board is ideal for backyards where complete visual screening is desired.
• Noise reduction – the overlapping boards and lack of gaps help dampen sound compared to standard picket fences.
• Wind protection – while not solid, the overlapping pattern reduces wind passage more than spaced pickets.
• Property line boundaries – the uniform appearance works well for long runs where aesthetics matter from both sides.

Limitations

This calculator provides estimates only. Actual material needs vary based on lumber dimensions, on-site conditions, and construction methods. It does not account for:

• Sloped or uneven terrain
• Gate construction materials
• Concrete or gravel for post footings
• Local building codes or setback requirements
• Custom board widths or non-standard lumber

Always consult a professional contractor for site-specific requirements and verify material quantities before purchasing.