Shiplap Calculator
Estimate shiplap boards, installed courses, linear stock, fasteners, package quantities and material cost after opening deductions.
Default project preview
28 boards
Net wall area
135 ft²
Installed courses
18
Base linear stock
294.5 ft
Fasteners
224
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Wall length
Enter this project assumption in ft. The current imperial default is 20 ft.
Wall height
Enter this project assumption in ft. The current imperial default is 8 ft.
Door and window area
Enter this project assumption in ft². The current imperial default is 25 ft². Minimum: 0.
Installed board face width
Enter this project assumption in in. The current imperial default is 5.5 in.
Stock board length
Enter this project assumption in ft. The current imperial default is 12 ft.
Cut and waste allowance
Enter this project assumption in %. The current imperial default is 10 %. Minimum: 0. Maximum: 50.
Fasteners per stock board
Enter this project assumption in a unitless value. The current imperial default is 8. Minimum: 0.
Fasteners per package
Enter this project assumption in a unitless value. The current imperial default is 250.
Price per stock board
Enter this project assumption in a unitless value. The current imperial default is 18. Minimum: 0.
Price per fastener package
Enter this project assumption in a unitless value. The current imperial default is 16. Minimum: 0.
How to read the outputs
Net wall area
openings deducted. Default preview: 135 ft².
Installed courses
based on face width. Default preview: 18.
Base linear stock
before waste. Default preview: 294.5 ft.
Fasteners
1 full packages. Default preview: 224.
Purchased stock
full board lengths. Default preview: 336 ft.
Material cost
boards and fasteners. Default preview: $520.00.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Linear stock = net wall area ÷ installed board face width. Waste is applied before dividing by stock length and rounding boards up.
Reviewed project guidance
How to use this estimate in a real project
Last reviewed: July 30, 2026
Estimate boards from net wall area and actual exposed face width rather than nominal board width.
Calculation steps
- 1Enter the actual project dimensions or operating values.
- 2Apply the calculator formula using consistent units.
- 3Review the unrounded result and the editable allowance.
- 4Round only to the product, stock length or equipment increment actually purchased.
Worked numerical example
A 12 ft × 8 ft wall using boards with a 5 in exposed face needs about 231 linear feet before cuts and waste.
Purchasing and rounding
Order shiplap using the board's actual exposed face after the rabbet or overlap is engaged. Convert each wall's required linear footage to available board lengths, planning joints and cut reuse by wall rather than rounding only the combined total.
Interpret the result
The coverage result is based on exposed face width, so nominal board width will overstate coverage. Openings can reduce net footage, while staggered joints, end trimming and unusable short offcuts can increase the number of full boards purchased.
Page-specific assumptions
- Inputs describe one consistent project condition.
- Entered yields and efficiencies match the selected product or equipment.
- Site-specific code and engineering requirements are checked separately.
Common mistakes
- Mixing imperial and metric inputs.
- Using nominal dimensions where actual coverage controls.
- Rounding intermediate values too early.
- Treating a quantity estimate as design approval.
Primary and technical references
BuildMeter provides planning estimates, not engineering, architectural, electrical, mechanical, plumbing, permit or code approval. Review the methodology and verify final decisions with product documentation and qualified professionals.
FAQ
Shiplap Calculator questions
Why use installed face width instead of nominal board width?+
Overlaps and profiles reduce the visible coverage of each course, so installed face width is the relevant dimension.
Should openings always be deducted?+
Large openings can be deducted, but offcuts around them may not be reusable.
Does this include corner and edge trim?+
No. Measure trim profiles separately based on the room layout.