Wood Fence Calculator

The quantity of lumber a wood fence needs depends on the total fence length, the maximum post spacing you are working to, the fence style, the actual board width, the gap or overlap between boards, the rails per section, any gate openings and the waste allowance you choose. Different wood fence styles count boards differently, which is why the calculator changes its board formula with the style you select:

• Sections = Run Length ÷ Maximum Post Spacing, rounded up — each run separately
• Posts = Sections + 1 for a simple open run
• Rails = Sections × Rails Per Section
• Spaced boards = Length ÷ (Board Width + Gap), rounded up
• Board-on-board = Length ÷ (Board Width − Overlap), rounded up
• Horizontal courses = Fence Height ÷ (Board Face Height + Vertical Gap), rounded up
• Panels = Length ÷ Panel Width, rounded up

1. 1Choose the wood fence style.
2. 2Enter the fence length, or switch to multiple runs and enter each side.
3. 3Enter the fence height and the maximum post spacing for your design.
4. 4Enter the rails per section for vertical board styles.
5. 5Enter the actual board or picket dimensions.
6. 6Enter the gap, overlap or panel size the style needs.
7. 7Add gates and corners if your layout has them.
8. 8Enter the post-hole dimensions if you want concrete included.
9. 9Choose the board waste or cut waste allowance.
10. 10Optionally enter your local material prices, then select Calculate.

Solid Privacy

Vertical boards with little or no intentional spacing.

Spaced Picket

Vertical pickets with deliberate gaps between boards.

Board-on-Board

Boards overlap, reducing the effective coverage per board.

Shadowbox

Boards alternate on opposite faces of the rails.

Horizontal

Boards run horizontally between the posts.

Prebuilt Panels

Factory-built fence panels installed between posts.

Each style is described so you can match the calculator to the fence you are building. BuildCalcWorks does not recommend one design over another.

Lumber's nominal size often differs from its actual finished dimensions — a board sold as a nominal size may measure less once it has been surfaced. For accurate material quantities, enter the actual face width of the board or picket you are using, measured from the material itself or taken from the product specification. The same applies to post dimensions used for the concrete calculation.

Overlapping boards each cover less of the run than their full width, so the calculation uses effective coverage:

• Effective Coverage = Board Width − Overlap
• Boards = Fence Length ÷ Effective Coverage, rounded up

With a 5.5 in board and a 1 in overlap, the effective coverage is 4.5 in. Over 100 ft (1,200 in) that gives 1,200 ÷ 4.5 = 266.67, which rounds up to 267 boards — and 294 boards with a 10% waste allowance. The overlap must be smaller than the board width, otherwise no board covers any of the fence and the calculator reports an error instead of a result.

Horizontal fencing is calculated from the height first. The number of courses is the fence height divided by the course pitch (board face height + vertical gap), rounded up. Multiplying the courses by the boarded length gives the total linear board length required. A 6 ft fence with 5.5 in boards and a 0.5 in gap has a 6 in pitch, so 72 ÷ 6 = 12 courses, and 12 × 100 ft = 1,200 linear ft of board. The stock-board count then depends on the board length you buy and the cut waste allowance you choose — offcuts are not assumed to be fully reusable.

Extra boards can be useful for cuts, knots and other defects, boards damaged in handling, and adjustments during layout. The allowance is yours to choose — no particular percentage is mandatory, and it is applied once: to the counted boards for vertical styles, or to the required board length for horizontal fencing.

When concrete is included, the calculator uses the same shared engine as the Post Hole Concrete Calculator: for round holes it works out the hole volume, subtracts the embedded post volume, and multiplies by the number of posts. Bag quantities, weight and volume conversions come from the same shared concrete and bag engines, so results match that calculator exactly for identical inputs.

You can enter your own local prices for posts, rails, boards or pickets, panels, horizontal stock boards, concrete bags, gates and hardware. Only the categories you price are included, and anything with a quantity but no price is shown as “Not priced” rather than as zero. For labor, removal of an old fence, delivery, fees and a full installed project budget, use the Fence Cost Calculator.

BuildCalcWorks estimates material quantities from the dimensions and layout you enter. Appropriate post spacing, post depth, lumber sizes, rail configuration and structural details depend on the project, site conditions and applicable local requirements.

• Spacing, hole depth, post size and rail count stay user inputs
• Gap, overlap and shadowbox spacing are entered, never assumed
• No structural, frost-depth, wind or code guidance is implied