TryBuildCalcWood Fence Calculator (Privacy / Picket / Board-on-Board)
Find your fence posts, rails, and pickets 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.
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
241
Privacy (butted), 5.5" 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): 241
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.
What Is a Wood Fence Calculator?
A wood fence calculator finds the number of posts, rails, and pickets/boards needed to build a privacy, picket, or board-on-board fence, plus the concrete needed for post footings — from your fence length, height, and style. It applies the same on-center spacing formulas used for stud walls, joists, and rafters, plus a rule-of-thumb footing depth cross-checked against a cited worked example.
This calculator computes material quantities only. It does not verify property line/setback compliance, local fence-height ordinances, or structural post adequacy for wind load.
Why fence style changes the picket count so much:
- Privacy uses butted boards (0" gap) — picket count is simply run length ÷ picket width
- Picket uses a real gap between boards, needing FEWER pickets than privacy for the same run
- Board-on-Board overlaps boards on both faces, needing MORE boards than privacy — each board only advances the run by its width minus the overlap
- Post bury depth always defers to your local frost line, which can require a much deeper hole than the height-based rule of thumb gives
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 | privacy | 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 | 5.5" |
| Total pickets (with 10% waste) | 241 |
Therefore, this 100 ft, 6 ft tall privacy fence needs approximately 14 posts, 43 rails, 241 pickets, and 37 bags of concrete.
Essential Checklist+−
Complete these critical checks before approving the work or proceeding to the next construction stage.
✓Layout & Style Inputs+-
- Total fence length confirmed from an actual field measurement or property survey, not assumed
- Property line location and any local setback requirement confirmed before laying out posts
- Fence height confirmed against local ordinance limits for this property (often lower at front vs. back/side yards)
- Utility locate service called (811 or local equivalent) before digging any post holes
✓Post & Footing Depth+-
- Computed post bury depth checked against the ACTUAL local frost line, not just the rule-of-thumb figure
✓Rail & Picket Quantities+-
- Picket/rail material (pressure-treated, cedar, or other) confirmed rated for the actual weather exposure and ground contact
Full QC Checklist+−
Verification checklist for wood privacy/picket fence material takeoffs — covering layout inputs, post/footing depth, rail/picket quantities, and installation/code confirmation. Use the Essential Checklist for critical checks before finalizing, expand to Full QC Checklist for complete verification.
✓Layout & Style Inputs+-
- Total fence length confirmed from an actual field measurement or property survey, not assumed
- Property line location and any local setback requirement confirmed before laying out posts
- Fence height confirmed against local ordinance limits for this property (often lower at front vs. back/side yards)
- Fence style selected (Privacy, Picket, or Board-on-Board) matches the actual design intent
- Utility locate service called (811 or local equivalent) before digging any post holes
✓Post & Footing Depth+-
- Computed post bury depth checked against the ACTUAL local frost line, not just the rule-of-thumb figure
- Post size (4x4 vs. 6x6) confirmed adequate for the actual fence height and local wind exposure
- Footing hole diameter confirmed reasonable for the actual post size and soil conditions
- Concrete footing cure time confirmed before attaching rails/pickets or applying any lateral load to posts
- Every post checked plumb (in both directions) and braced before the concrete sets, not just eyeballed
✓Rail & Picket Quantities+-
- Rail count confirmed to match the actual fence height, not just a generic assumption
- Picket pitch (width + gap, or width − overlap) verified against a physical layout before cutting the full run
- Picket/rail material (pressure-treated, cedar, or other) confirmed rated for the actual weather exposure and ground contact
- Picket count confirmed to exclude gate opening widths, not double-counted across the full raw fence length
- Fastener pattern (typically 2 per picket per rail) confirmed adequate for the actual picket width and expected wind exposure
✓Installation & Code+-
- Fence "good side" (finished face, no rails visible) orientation confirmed facing the neighbor/street, per local custom or agreement
- Gate posts confirmed adequately reinforced (larger post, deeper footing, or diagonal brace) for the actual gate weight and swing
- Corner and end posts confirmed adequately braced — they carry different loads than mid-run line posts
- Local code amendments (pool-barrier self-closing gate rules, HOA material/color restrictions) checked before finalizing
- Total post/rail/picket counts reconciled against the actual site layout before ordering lumber
Fence Reference Tables
Rail count by fence height, and picket pitch by style.
| Fence Height | Rails per Section |
|---|---|
| 3 ft | 2 |
| 4 ft | 2 |
| 5 ft | 3 |
| 6 ft | 3 |
| 7 ft | 4 |
| 8 ft | 4 |
Fence Styles
| Style | Typical Gap/Overlap | Description |
|---|---|---|
| Privacy | 0" (butted) | Complete visual screening — pickets butted directly together, most common 6 ft residential fence style. |
| Picket | 1.5-2" gap | Classic open look with visible gaps between boards — commonly shorter (3-4 ft) front-yard fences. |
| Board-on-Board | 1-1.5" overlap | Alternating overlapped boards on both faces — full privacy plus some airflow, finished look from both sides. |
When should you use this wood fence calculator?
- Planning post, rail, and picket quantities before ordering lumber for a new fence.
- Comparing how fence style (privacy vs. picket vs. board-on-board) changes the picket count for the same run.
- Sizing concrete footings and estimating bag count for post-setting.
- Budgeting a fence project with gates included in the material count.
- Cross-checking a contractor's fence material quote against an independent estimate.
Quick Fence-Building Tips
- Call 811 (or your local utility locate service) before digging any post holes — every time, even on a property you've dug on before.
- Set corner and end posts first, string a line between them, then set line posts to that line for a straight, consistent fence.
- Add a few inches of gravel at the bottom of each footing hole for drainage — reduces post rot at the base over time.
- Use at least 2 fasteners per picket-rail intersection — a single fastener lets boards twist loose over time.
- Consider upsizing or bracing gate posts specifically — they carry more concentrated load than a typical line post.
- Dry-fit a short test section of pickets before cutting the full run, to confirm your actual gap/overlap looks right.
Common Mistakes
- Setting posts without confirming the local frost line — a shallow footing can heave in freeze-thaw cycles.
- Not checking the property line/setback before laying out posts, leading to a fence that has to be moved.
- Using the same post size and footing for gate posts as regular line posts, without reinforcing for the extra load.
- Building an untreated or non-decay-resistant fence, especially near ground contact.
- Attaching rails/pickets before the concrete footing has adequately cured.
- Forgetting local ordinance limits — front-yard height caps are often lower than back/side yard limits.
- Skipping the utility locate call before digging, risking hitting a buried line.
Limitations
- Standard US residential wood fence construction, one straight uniform-height run at a time — a fence with corners or varying height needs each section calculated separately.
- Post bury depth is a rule of thumb (height ÷ 2) — always verify against your local frost line, which governs whenever it's deeper.
- Does not verify property line/setback compliance, local fence-height ordinances, or pool-barrier gate requirements.
- Does not verify structural post adequacy for wind load — taller fences or high-wind sites may need a larger post than this calculator assumes.
- Does not count fasteners, post caps, or gate hinge/latch hardware beyond the gate count shown.
- Gate posts use the same size/footing as regular posts — consider upsizing or bracing them separately for the extra load a gate concentrates.
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.