🪵 Shiplap Calculator
Calculate shiplap boards needed for your wall project
Width that shows after overlap (less than board width)
How to Use This Calculator
Enter Wall Dimensions
Input the length and height of your wall in feet. Measure the total wall area where you'll be installing shiplap siding or wall treatment.
Specify Board Width
Select your shiplap board width in inches. Standard is 6 inches, but boards come in various widths (4, 6, 8, 12 inches). Wider boards cover more area with fewer pieces.
Set Exposure Width
Select exposure width (the width that shows after boards overlap). Exposure width is less than board width because boards overlap. Standard is 5.5 inches for 6-inch boards.
Calculate and Order
Click "Calculate Shiplap" to see boards needed, number of rows, and linear feet. Add 10% extra for waste. Order shiplap boards from lumber suppliers or home improvement stores.
Formula
Wall Area (sq ft) = Length (ft) × Height (ft)
Number of Rows = Wall Height (inches) ÷ Exposure Width (inches)
Boards per Row = Wall Length (inches) ÷ Board Width (inches)
Total Boards = Boards per Row × Number of Rows × 1.10 (with waste)
Example 1: Standard Wall (20 ft × 8 ft, 6" boards, 5.5" exposure)
Step 1: Calculate wall area: 20 × 8 = 160 sq ft
Step 2: Convert height: 8 ft = 96 inches
Step 3: Calculate rows: 96 ÷ 5.5 = 17.5 → 18 rows
Step 4: Calculate boards per row: (20 × 12) ÷ 6 = 240 ÷ 6 = 40 boards per row
Step 5: Calculate total boards: 40 × 18 = 720 boards
Step 6: Add waste: 720 × 1.10 = 792 boards (with 10% waste)
Example 2: Larger Wall (30 ft × 9 ft, 8" boards, 7.25" exposure)
Step 1: Calculate wall area: 30 × 9 = 270 sq ft
Step 2: Convert height: 9 ft = 108 inches
Step 3: Calculate rows: 108 ÷ 7.25 = 14.9 → 15 rows
Step 4: Calculate boards per row: (30 × 12) ÷ 8 = 360 ÷ 8 = 45 boards per row
Step 5: Calculate total boards: 45 × 15 = 675 boards
Step 6: Add waste: 675 × 1.10 = 743 boards (with 10% waste)
About Shiplap Calculator
The Shiplap Calculator is an essential tool for homeowners, contractors, carpenters, and DIY enthusiasts who need to accurately determine how many shiplap boards are required for their shiplap siding or wall treatment projects. This calculator eliminates guesswork by providing precise board counts based on wall dimensions, board width, and exposure width, helping you order the right amount of materials without waste or shortages.
When to Use This Calculator
- Interior Accent Walls: Calculate shiplap boards needed for interior accent walls or feature walls
- Exterior Siding: Determine materials for shiplap exterior siding installation
- Room Remodeling: Estimate shiplap quantities for room remodeling and renovation projects
- Budget Planning: Calculate material costs by determining exact board quantities needed
- Contractor Estimates: Quick reference for contractors bidding shiplap installation projects
Why Use Our Calculator?
- ✅ Accurate Board Count: Precise calculations prevent over-ordering or running short
- ✅ Exposure Calculation: Accounts for board overlap in shiplap installation
- ✅ Row Calculation: Determines number of rows needed based on wall height and exposure width
- ✅ Multiple Configurations: Supports different board widths (4, 6, 8, 12 inches) and exposure widths
- ✅ Cost Planning: Helps budget accurately by determining exact material needs
- ✅ Time Savings: Instant calculations eliminate manual math and measurements
Common Applications
Interior Accent Walls: Homeowners and contractors planning shiplap accent walls use this calculator to order the correct quantity of shiplap boards. Standard interior shiplap uses 6-inch boards with 5.5-inch exposure, which this calculator helps determine accurately.
Exterior Siding: Contractors and homeowners planning shiplap exterior siding use this tool to estimate materials needed. Exterior shiplap typically uses similar dimensions to interior but may require weather-resistant materials.
Room Remodeling: DIY enthusiasts and contractors planning room renovations use this calculator to determine shiplap quantities needed, ensuring sufficient materials are on-site before starting work.
Tips for Best Results
- Board Widths: Standard is 6 inches; wider boards (8-12") use fewer pieces but cost more
- Exposure Width: Exposure width is less than board width due to overlap—standard is 5.5" for 6" boards
- Add Waste: Always add 10% extra for waste, cuts around doors and windows, and mistakes
- Installation: Shiplap boards overlap—each board covers part of the board below it
- Order Together: Order all boards from the same batch for color consistency
Frequently Asked Questions
How many shiplap boards do I need for a 20×8 foot wall?
For a 20×8 foot wall using 6-inch boards with 5.5-inch exposure, you'll need approximately 792 boards (with 10% waste). Without waste, you'd need 720 boards (40 boards per row × 18 rows). Always add 10% extra for cuts and mistakes.
What is shiplap?
Shiplap is a type of wooden board with rabbeted edges (notched edges) that allow boards to overlap each other when installed horizontally. It creates a distinctive horizontal line pattern popular for farmhouse, rustic, and modern interior design styles.
What's the difference between board width and exposure width?
Board width is the actual width of the shiplap board. Exposure width is the width that shows after boards overlap. For 6-inch boards, exposure width is typically 5.5 inches (0.5 inches overlap per board). The overlap prevents gaps and provides weather protection.
Do I need to add extra boards for waste?
Yes! Always add 10% extra for waste, cuts around doors and windows, and mistakes during installation. If you need 720 boards, order about 792 boards (with 10% waste) to ensure you have enough material.
What size shiplap boards should I use?
Standard shiplap board width is 6 inches with 5.5-inch exposure. Wider boards (8-12 inches) use fewer pieces but cost more. Narrower boards (4 inches) use more pieces but may look busy. Choose based on appearance preference and budget.
Can I use shiplap outdoors?
Yes! Shiplap can be used for exterior siding, but it requires weather-resistant materials and proper installation. Use cedar or treated shiplap for exterior applications. Proper sealing and maintenance are essential for outdoor shiplap.