Shiplap Wall Calculator

Design flawless shiplap walls with pro-grade accuracy and control. Calculate boards, exposure, gaps, trims, and exact waste allowances. Handle multiple walls, openings, orientation, and seam staggering options. Estimate cost, nails, and adhesives with confidence quickly. Build smarter plans, fewer offcuts, and cleaner finishes consistently.

Project Inputs
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Board Profile

Walls
# Length (ft) Height (ft) Notes
Openings (subtract)
# Width (ft) Height (ft) Type
Results
Run a calculation to see results.

Per-Wall Details
# Area (sq ft) Courses / Boards Studs Fasteners
Formulas Used

Exposed face width = board_width − overlap + gap.
Coverage per board = exposed_face_width × board_length.
Net area = Σ(wall_length × wall_height) − Σ(opening_width × opening_height).
Boards required ≈ ⌈(net_area ÷ coverage_per_board) × (1 + waste%)⌉.
Horizontal: courses_per_wall ≈ ⌈wall_height ÷ exposed_face_width⌉.
Vertical: boards_across_width ≈ ⌈wall_length ÷ exposed_face_width⌉.
Fasteners (horizontal) ≈ Σ(courses_per_wall × studs_per_wall × fasteners_per_stud).
Fasteners (vertical) ≈ Σ(boards_across_width × rows_along_height × fasteners_per_stud).
Studs_per_wall ≈ ⌊wall_length ÷ stud_spacing⌋ + 1; rows_along_height ≈ ⌊wall_height ÷ stud_spacing⌋ + 1.

How to Use
  1. Select units and orientation.
  2. Enter board profile: width, length, overlap, and gap.
  3. Add each wall’s length and height; add windows and doors.
  4. Adjust waste, stud spacing, and fasteners per stud as needed.
  5. Optionally enter cost per board or per area for estimates.
  6. Click Calculate to see totals and per-wall details.
  7. Use Download CSV or Download PDF to export.
Example Data Table
Click “Load Example” to auto-fill
Scenario Walls (L×H) Openings Board (W×L) Overlap/Gaps Waste
Typical living room feature wall 12 ft × 8 ft (one wall) 1 window 3 ft × 4 ft 5.5 in × 96 in 0.5 in overlap, 0 in gap 10%
Shiplap Yield & Coverage Reference

Quick reference for common nominal board sizes with a 0.5 in overlap and default 96 in length. Coverage assumes no decorative gap.

Nominal size Board width (in) Overlap (in) Gap (in) Exposed face (in) Length (in) Coverage / board (sq ft)
1×6 5.5 0.5 0 5.0 96 3.33
1×8 7.25 0.5 0 6.75 96 4.50
1×4 3.5 0.5 0 3.0 96 2.00

Use the calculator for exact values when you change length, overlap, or add a decorative gap.

Recommended Gaps, Finishes, and Waste Factors

Guidelines vary by material, climate, and quality goals. Adjust to match your supplier recommendations and site conditions.

Scenario Suggested gap Typical finish Typical waste % Notes
Paint‑grade interior 0–1/16 in Primer + paint 10–12% Minimal gap hides seams; caulk corners and trims.
Stain‑grade interior 1/16–1/8 in Clear or polyurethane 12–15% Increase waste for color/figure matching.
Exterior protected wall ~1/8 in Exterior paint/seal 15–18% Account for end sealing and weather‑exposed cuts.
Feature patterns (chevron/diagonal) 1/16 in Paint or stain 18–22% Extra offcuts from angle joints and staggering.

For hardwoods or humid environments, acclimate boards and consider larger gaps to accommodate movement.

FAQs

It’s the visible height of each board course after overlapping rabbets and any planned gap; use width − overlap + gap.

Area is identical; counts differ due to course math and seam layout. The calculator models both orientations consistently.

It assumes uniform stud spacing and two fasteners per board per stud. Adjust the inputs for your fastening pattern.

This tool estimates boards and fasteners. Add linear-footage trims separately; export CSV to extend with your trim schedule.

Yes. Cuts, defects, and color matching create offcuts. Start with 10–15% and adjust to your project and skill.

Openings reduce area but don’t always reduce courses. You’ll still usually run courses across the full wall, trimming around openings.

For simplicity we assume one standard length. If you mix lengths, aim for balanced staggering and increase waste to cover extra cuts.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.