Fence Material Calculator

Calculation methodology by fence style

Every run is processed from its actual length. Gate start and end points divide it into uninterrupted fence segments. Each segment uses ceil(segment length ÷ maximum spacing); posts at identical gate edges or connected run corners are merged, with gate classification taking priority over corner and end classification.

• Solid privacy and spaced picket: boards per segment are rounded from length divided by actual board width plus clear gap. Optional matching layers multiply the board count.
• Board-on-board: board pitch is actual face width minus overlap. This is calculated directly, not as two generic finished sides.
• Shadowbox: each face is a row of boards at actual width plus the same-side gap; the two alternating rows are added.
• Horizontal slat: courses are rounded from fence height divided by slat face plus vertical gap. Each course is cut into stock pieces for every section.
• Prebuilt panel: every separately rounded section requires one panel; confirm the selected panel can be trimmed for short end sections.
• Post-and-rail: each rail row is cut to every post-to-post section; no picket or panel infill is claimed.
• Rails and stock: stock pieces are rounded for each post-to-post section, then waste is applied. This avoids assuming offcuts can always be reused across unrelated sections.
• Concrete: net volume per installed post is the cylindrical hole below the gravel base minus the embedded post cross-section. Bag counts divide waste-adjusted volume by the selected approximate yield and round up.

Dimensional presets are editable assumptions, not universal spacing, burial, or code rules. The Western Red Cedar Lumber Association prebuilt-panel guide illustrates that panels are sold by section and actual systems vary. QUIKRETE's post-setting calculator and Fast-Setting Concrete data sheet support geometry-based post-hole estimates and the approximate bag yields used here. Verify the yield printed on the product you buy.

How to measure and estimate fence materials

1. Measure every run: Measure each straight run along the fence line, including any gate openings, and note which consecutive runs share a corner post.
2. Locate each gate: For each gate, record its opening width and the distance from the start of its assigned run to the near edge of the opening.
3. Choose style and spacing: Select the construction style, fence height, and maximum center-to-center post spacing, then review the populated style defaults.
4. Confirm stock and footing details: Open Advanced options to confirm actual board or panel dimensions, rail lengths, waste, post-hole geometry, and optional gravel.
5. Review and price the order: Calculate, check the run and gate breakdown, enter optional supplier unit prices, and copy, download, or print the final bill of materials.

Worked fence calculator examples

Example 1: 100-foot, 6-foot privacy fence with one 4-foot gate

Inputs: one 100 ft run, gate from 48 ft to 52 ft, 8 ft maximum spacing, 5½ in butted boards, three rail rows, 10% board/rail waste, and 5% post waste. The gate creates 48 ft and 48 ft fence segments. Each becomes ceil(48 ÷ 8) = 6 sections, for 12 sections total. Posts are 2 ends + 2 gate posts + 10 line posts = 14 required; 5% spare rounds the order to 15. Each 48 ft fence segment needs 105 boards and the separately rounded 4 ft gate needs 9, for 219 base boards and 241 after 10% waste. Three rails across twelve 8 ft sections require 36 rail boards, plus three gate-frame pieces; 10% rail waste applies to fence rails.

Example 2: two unequal prebuilt-panel runs

With 6 ft panels, a 17 ft run needs ceil(17 ÷ 6) = 3 panels and a separate 25 ft run needs ceil(25 ÷ 6) = 5. The correct total is 8 panels. Averaging the runs or rounding only the combined 42 ft would produce 7 panels and miss one section.

Planning limits

This is a material and cost estimator, not a structural or building-code design. Confirm utility locations before digging. Fence height, frost depth, soil, drainage, wind exposure, slope, gate weight, post material, fasteners, bracing, property setbacks, local requirements, and manufacturer instructions can change the design and quantities.

Fence material FAQs

How many posts are needed for 100 feet of fence?

For one straight 100-foot run with no gate, 8-foot maximum spacing creates 13 sections and 14 posts. Corners, gates, separate runs, and different spacing change the count.

Should fence posts be 6 or 8 feet apart?

Use the maximum spacing specified for the selected fence system and site conditions. Six-foot spacing creates shorter, stiffer sections; 8-foot spacing uses fewer posts. Wind, height, soil, rails, panels, and manufacturer instructions can require closer spacing.

How many rails does a 6-foot fence typically use?

Many 6-foot vertical-board fences use three rail rows, but this is a preset, not a universal rule. Follow the chosen system or design and override the rail count when necessary.

What is nominal versus actual picket width?

Nominal size is the trade name; actual face width is the measured finished board width. Enter actual width because even a small difference changes the picket count across a long run.

How do gates affect fence material counts?

Each gate removes its opening from adjacent fence segments and normally adds a post at each edge. Gates split a run, so the calculator rounds the sections on both sides separately and adds gate framing, hinges, and a latch set.

How do board-on-board and shadowbox quantities differ?

Board-on-board uses an overlap pitch equal to board width minus overlap. Shadowbox uses alternating faces and estimates two board rows using board width plus the same-side gap. Their quantities should not be estimated as ordinary side-by-side pickets.

How should I measure an irregular fence boundary?

Measure every straight run separately along the fence line. Add a run at each corner or direction change, mark when its starting corner shares the previous run's ending post, and position each gate from the start of its assigned run.

How do slopes affect fence waste?

Slopes can require stepped panels, racked sections, angled cuts, or longer posts. Increase waste when cuts cannot be reused and confirm that the selected panel or fence system can follow the slope.

How are concrete bags calculated?

The calculator finds the cylindrical hole volume below the gravel base, subtracts the embedded post volume, multiplies by installed posts, adds concrete waste, and divides by the selected bag yield before rounding up.

Is this a structural or building-code design tool?

No. Frost depth, soil, wind exposure, fence height, gate loads, utilities, local rules, and manufacturer requirements determine final spacing, post size, embedment, and footing design.