Shiplap Calculator — How many boards do I need?
Get instant material estimates for your shiplap project with waste factor, cost calculations, and exportable shopping lists. Perfect for accent walls, ceilings, and full room installations.
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Shiplap Calculator: How It Works
Our shiplap calculator takes the guesswork out of material estimation by calculating exactly how many boards you need based on your wall dimensions, board specifications, and project complexity. Whether you’re planning a simple accent wall or an entire room, this tool ensures you purchase the right amount of material while accounting for necessary waste.
The calculator uses these formulas to determine your material needs:
Note: All calculations round up to the nearest whole board to ensure you have enough material.
Common Shiplap Board Sizes
Understanding shiplap board dimensions is crucial for accurate planning. The most common face widths available are:
5.25-inch boards: This narrow profile creates a more traditional, detailed look with more seams. Perfect for smaller spaces or when you want a busier pattern.
7.25-inch boards: The most popular choice for modern shiplap installations. This width provides a balanced look that works well in most rooms and is widely available.
8-inch boards: Offers a cleaner, more contemporary appearance with fewer seams. Ideal for large walls where you want to minimize visual breaks.
Remember that the actual board width is typically 0.5-1 inch wider than the face measurement to account for the overlapping tongue and groove system that creates the characteristic shiplap reveal.
Waste Factor Advice for Shiplap Projects
Properly accounting for waste is essential to avoid mid-project delays and extra trips to the lumber yard. The amount of waste you should factor depends on your project’s complexity:
5% Waste: Suitable for simple, rectangular walls with no obstacles. Use this for basic accent walls with minimal cutting.
10% Waste (Recommended): Standard for most projects including walls with electrical outlets, simple corners, or basic pattern work.
15% Waste: Recommended for complex installations with multiple corners, windows, doors, or when working with expensive materials where you want to ensure grain matching.
20%+ Waste: Reserve for intricate patterns like herringbone, diagonal installation, or when working with highly figured wood where grain matching is important.
Always keep a few extra boards for future repairs or touch-ups, especially if you’re using a specific dye lot or wood batch that might not be available later.
Case Study: 10×12 Foot Accent Wall
Let’s walk through a real-world example using our shiplap calculator for a 10-foot wide by 12-foot high accent wall with one 3×4 foot window.
Inputs:
– Wall dimensions: 10′ wide × 12′ high
– Window area: 12 square feet (3’×4′)
– Board face width: 7.25 inches
– Board length: 8 feet
– Waste factor: 10%
Calculations:
Total wall area: 10 × 12 = 120 sq ft
Net area after window: 120 – 12 = 108 sq ft
Boards per row: 10 feet ÷ (7.25 inches ÷ 12) = 16.55 → 17 boards
Number of rows: 12 feet ÷ (7.25 inches ÷ 12) = 19.86 → 20 rows
Raw boards needed: 17 × 20 = 340 boards
With 10% waste: 340 × 1.10 = 374 boards
Total linear feet: 374 × 8 = 2,992 linear feet
This example demonstrates why accurate calculation is essential—what might seem like a simple wall actually requires significant material when accounting for the overlap pattern and waste.
Frequently Asked Questions
For a 10×12 wall using 7.25-inch wide boards at 8 feet long, you’ll need approximately 20 boards with 5% waste factor, totaling 160 linear feet. Always round up to account for cuts and pattern matching. Use our calculator above for precise measurements based on your specific board dimensions.
The face width is the visible portion after installation. Common sizes are 5.25″, 7.25″, and 8″ but the actual board width is typically 0.5-1″ wider to account for the overlapping tongue and groove. Always use the face width measurement in calculations, not the total board width.
Add 5-10% waste for simple walls, 10-15% for rooms with many corners/outlets, and 15-20% for complex patterns like herringbone. Our calculator automatically suggests waste based on project complexity but allows manual adjustment for your specific needs.
Boards count the individual pieces needed, while linear feet measures total length of material. If you need 20 boards that are 8 feet long, that’s 160 linear feet total. Lumber yards often price by linear foot, while retail stores typically sell by the board.
Measure each wall separately, then add the totals. Our multi-wall mode lets you input different dimensions for each wall and automatically calculates the combined material needs. This ensures accurate estimates for entire rooms with varying wall sizes.
Material costs range from $2-8 per board, while professional installation adds $3-7 per square foot. DIY installation costs are primarily materials plus tools if needed. Our cost calculator helps estimate both material and labor expenses for budgeting.
Yes, mixing board lengths can reduce waste. Use longer boards for main sections and shorter pieces for above/below windows or between openings. Our calculator helps optimize board usage across your entire project to minimize material waste.
Add extra waste percentage for corners (typically 2-5% per corner) and measure around outlets rather than subtracting them. Our calculator includes preset waste factors for these scenarios and allows customization based on your specific project complexity.
Related Tools: Check out our other construction calculators including Tile Calculator, and Paint Calculator for complete project planning.
For detailed installation guidance, visit our Shiplap Measurement Guide with step-by-step instructions and pro tips.