TryBuildCalcBoard-on-Board Fence Calculator (Overlapped, Both Sides)
Size your board-on-board fence instantly.
🕒 Last updated: September 4, 2026
Inputs
ℹ️Total linear run — confirm against an actual property survey, not just a fence-line guess.
ℹ️Above-ground height — check local ordinance limits, which are often lower at front yards than back/side yards.
ℹ️Privacy: butted boards, 0 gap. Picket: real gap between boards. Board-on-Board: overlapped on both faces — uses more boards than privacy for the same run.
ℹ️Typically 1-1.5in — offsets natural wood shrinkage and prevents gaps from opening over time.
ℹ️4x4 is standard for most fences up to 6 ft; 6x6 gives more margin for taller fences, gate posts, or high-wind sites.
Waste
ℹ️Applied to rails and pickets — 10% is a common estimating default. Not applied to the fixed post or concrete bag counts.
Cost
Posts Needed
14
4x4, 9.0 ft each (3.0 ft buried)
Pickets / Boards Needed
294
Board-on-Board (overlapped), 4.5" pitch
Posts & Footings
Sections (8 ft O.C.): 13
Footing hole: 10.5" dia × 3.0 ft deep
Concrete per post: 1.55 cu ft
Concrete bags (80 lb): 37
Rails & Pickets
Rails per section: 3 (1 per 24" of height)
Total rails (+10% waste): 43
Picket run length: 100 ft
Total pickets (+10% waste): 294
Assumptions Used
Standard US residential wood fence construction. Post count follows the same "one per spacing, minimum 2" on-center formula used elsewhere on this site — 6-8 ft O.C. is standard, tighter for softer soil or high-wind areas. Rail count follows the widely-used "one rail per 24" of height" rule (2 rails for a 4 ft fence, 3 for a 6 ft privacy fence). Post bury depth is a rule-of-thumb (buried = fence height ÷ 2, derived from "bury 1/3 of total post length") — always verify against your local frost line, which governs whenever it's deeper than this rule gives. Footing hole diameter assumes roughly 3× the post's own width; concrete volume subtracts the post's own cross-section from the hole. Picket/board count uses the entered style's effective pitch (0" gap for privacy, a real gap for picket, an overlap for board-on-board). Waste applies to rails/pickets only, not to the fixed post or concrete bag counts. This calculator computes material quantities only — it does not verify structural post embedment for wind load, local fence-height ordinances/setbacks, or property line surveys.
Bill of Materials
Main material: 14 pcs + recommended tools
+−
Bill of Materials
Main material: 14 pcs + recommended tools
Computed items reflect your entered length, height, and style; consumables below are general recommendations — actual needs vary by product and site conditions.
For Your Job
Fence Posts
Pickets / Boards
Rails
Concrete
General Tools & Consumables
Post caps
Galvanized or stainless fasteners
Gate hinges & latch hardware
Post level / string line
Post hole digger or auger
Circular saw / miter saw
Level
Tape measure
Gravel (footing drainage)
Safety glasses & work gloves
Diagram simplified for clarity (not to scale, 3 posts shown regardless of actual count) — picket spacing shown schematically for the selected style.
Looking for the verification checklist, reference tables, tips, or common mistakes?See the complete Wood Fence Calculator.
Board-on-board fence material takeoff
Board-on-board alternates overlapping boards on both faces of the fence, giving full privacy with a small amount of airflow through the overlap — needing MORE boards than a simple butted privacy fence for the same run.
This page defaults to a 100 ft run at 6 ft height with 1x6 boards and a 1" overlap — edit the inputs above to match your actual fence.
Wood Fence Calculator Formula: How Is It Determined?
Post, rail, and picket quantities, plus footing volume, calculated separately and combined into a material takeoff.
Step 1 — Posts & Footings
Posts = max(2, ceil(Fence Length / Post Spacing) + 1) + 2 per gate
Buried Depth = Fence Height / 2 (derived from "bury 1/3 of total post length")
Footing Hole Diameter = ~3 x Post Width
Concrete per Post = Hole Volume - Post's Own Cross-Section Volume
Post count follows the same "one per spacing, minimum 2" formula used for deck posts elsewhere on this site. Buried depth is a rule of thumb, cross-checked against a cited worked example (6 ft fence, 9 ft post, 36" buried) — your LOCAL FROST LINE always governs when it's deeper.
Step 2 — Rails
Rails per Section = ceil(Fence Height (in) / 24)
Total Rails = Rails per Section x Number of Sections
One rail per 24" of fence height — 2 rails for a 4 ft fence, 3 for a 6 ft privacy fence, 4 for 8 ft — a widely-used rule of thumb, confirmed against multiple independent sources.
Step 3 — Pickets / Boards
Effective Pitch = Picket Width + Gap (Privacy: 0 gap, Picket: real gap, Board-on-Board: negative gap/overlap)
Picket Run Length = Fence Length - Total Gate Width
Pickets = ceil(Picket Run Length (in) / Effective Pitch)
One formula covers all 3 styles — only the gap value changes: zero for privacy's butted boards, a positive gap for picket-style, or a negative gap (overlap) for board-on-board, which needs more boards since each one only advances the run by width-minus-overlap.
Worked Example
This example walks through your current inputs above, using the same steps as the Formula section.
Input Values Used
| Input | Value | Why it is used |
|---|---|---|
| Length / height | 100 ft / 6 ft | Sets post/rail/picket counts |
| Style | boardOnBoard | Sets picket pitch |
| Post spacing / size | 8 ft / 4x4 | Sets post count and footing size |
Step 1 — Posts & Footings
| Calculation | Result |
|---|---|
| Sections | 13 |
| Total posts | 14 |
| Buried depth / post length | 3.0 ft / 9.0 ft |
| Concrete bags | 37 |
Step 2 & 3 — Rails & Pickets
| Calculation | Result |
|---|---|
| Rails per section | 3 |
| Total rails (with 10% waste) | 43 |
| Effective picket pitch | 4.5" |
| Total pickets (with 10% waste) | 294 |
Therefore, this 100 ft, 6 ft tall boardOnBoard fence needs approximately 14 posts, 43 rails, 294 pickets, and 37 bags of concrete.
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Disclaimer: This calculator provides approximate results for planning and estimation purposes only. Actual requirements may vary based on site conditions, materials, workmanship, and local building regulations. Always consult a qualified engineer, architect, or construction professional before making final decisions.