Shiplap Calculator
Estimate the shiplap boards needed for your project
Calculate Shiplap Needed
What is a Shiplap Calculator?
A shiplap calculator is a specialized tool designed to help homeowners, DIY enthusiasts, and contractors estimate the amount of shiplap material needed to cover a specific wall or area. It takes into account the dimensions of the wall (width and height), the actual coverage width of the shiplap boards (after the overlap), the length of the boards, and an allowance for wastage due to cuts and fitting.
This calculator simplifies the process of determining how many boards to purchase, preventing both under-buying (which leads to project delays) and over-buying (which wastes money). It’s particularly useful for projects involving accent walls, full room paneling, or even ceilings where shiplap is used.
Anyone planning a shiplap installation project should use a shiplap calculator. Common misconceptions include thinking you can just divide the wall area by the board area without considering the overlap (rabbet joint) and wastage, which will lead to a shortage of materials.
Shiplap Calculator Formula and Mathematical Explanation
The shiplap calculator uses the following steps:
- Calculate Wall Area: Multiply the wall width by the wall height.
Wall Area (sq ft) = Wall Width (ft) * Wall Height (ft) - Calculate Board Coverage Area: Convert the actual board coverage width from inches to feet and multiply by the board length.
Board Coverage (sq ft) = (Board Width (in) / 12) * Board Length (ft) - Calculate Boards Needed (No Waste): Divide the total wall area by the coverage area of one board.
Boards (No Waste) = Wall Area / Board Coverage - Add Wastage: Multiply the number of boards (no waste) by (1 + Wastage Percentage / 100).
Total Boards = Boards (No Waste) * (1 + Wastage / 100) - Round Up: Since you can’t buy fractions of boards, round the Total Boards up to the nearest whole number.
- Total Linear Feet: Multiply the total number of boards (rounded up) by the length of each board.
Total Linear Feet = Total Boards * Board Length (ft) - Estimated Cost (Optional): Multiply the total number of boards by the cost per board.
Estimated Cost = Total Boards * Cost Per Board
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| Wall Width | Width of the area to be covered | feet | 5 – 30 |
| Wall Height | Height of the area to be covered | feet | 7 – 12 |
| Board Width | Actual coverage width of one board | inches | 3 – 7.5 |
| Board Length | Length of one shiplap board | feet | 6 – 16 |
| Wastage | Percentage allowance for cuts | % | 5 – 15 |
| Cost Per Board | Price of a single shiplap board | $ | 5 – 30 |
Practical Examples (Real-World Use Cases)
Example 1: Accent Wall
Sarah wants to install shiplap on an accent wall that is 10 feet wide and 8 feet high. She’s using shiplap boards with an actual coverage width of 5 inches and they come in 8-foot lengths. She anticipates 10% wastage and each board costs $9.
- Wall Width: 10 ft
- Wall Height: 8 ft
- Board Width: 5 in
- Board Length: 8 ft
- Wastage: 10%
- Cost Per Board: $9
Using the shiplap calculator:
Wall Area = 10 * 8 = 80 sq ft
Board Coverage = (5/12) * 8 = 3.333 sq ft
Boards (No Waste) = 80 / 3.333 = 24 boards
Total Boards = 24 * (1 + 10/100) = 24 * 1.1 = 26.4, rounded up to 27 boards.
Total Linear Feet = 27 * 8 = 216 linear feet
Estimated Cost = 27 * $9 = $243
Sarah needs to buy 27 boards. For more info on installation, check our guide on how to install shiplap.
Example 2: Larger Room Section
David is covering a section of a wall that is 15 feet wide and 9 feet high with shiplap that has a 6-inch coverage width and comes in 12-foot lengths. He estimates 15% waste due to a window cutout, and boards cost $15 each.
- Wall Width: 15 ft
- Wall Height: 9 ft
- Board Width: 6 in
- Board Length: 12 ft
- Wastage: 15%
- Cost Per Board: $15
The shiplap calculator shows:
Wall Area = 15 * 9 = 135 sq ft
Board Coverage = (6/12) * 12 = 6 sq ft
Boards (No Waste) = 135 / 6 = 22.5 boards
Total Boards = 22.5 * (1 + 15/100) = 22.5 * 1.15 = 25.875, rounded up to 26 boards.
Total Linear Feet = 26 * 12 = 312 linear feet
Estimated Cost = 26 * $15 = $390
David will need 26 boards. He might also want to estimate paint using our paint calculator if he plans to paint the shiplap.
How to Use This Shiplap Calculator
- Enter Wall Dimensions: Input the width and height of the wall area you plan to cover with shiplap, in feet.
- Specify Board Details: Enter the actual coverage width of your shiplap boards in inches (the part you see after installation) and the length of each board in feet.
- Estimate Wastage: Input a percentage for wastage. 10% is a good starting point, but increase it for complex walls with many cuts or windows.
- Add Cost (Optional): If you know the cost per board, enter it to get an estimated total material cost.
- View Results: The shiplap calculator will instantly show the total number of boards needed (rounded up), total linear feet, and estimated cost if applicable. The table and chart provide a further breakdown.
- Adjust and Recalculate: Change any input value, and the results will update automatically.
The primary result tells you the minimum number of boards to purchase. Always round up, and consider buying an extra board or two for unforeseen issues.
Key Factors That Affect Shiplap Calculator Results
- Wall Dimensions: Larger walls naturally require more boards. Accurate measurements are crucial.
- Board Coverage Width: Wider boards cover more area per board, reducing the number of boards but also changing the look. The overlap is key here – use the *actual* coverage width.
- Board Length: Longer boards can mean fewer seams but might lead to more waste if the wall width isn’t a multiple of the board length.
- Wastage Percentage: Complex walls with windows, doors, or angled cuts will increase wastage. It’s better to overestimate wastage slightly.
- Installation Pattern: A standard horizontal or vertical installation is assumed. Diagonal or herringbone patterns significantly increase waste and are not directly calculated here (you’d need a much higher waste percentage).
- Board Quality and Defects: If some boards have defects and are unusable, your actual waste might be higher than estimated.
Considering these factors helps you refine your wastage percentage for a more accurate estimate from the shiplap calculator. Explore different interior design trends to see how shiplap is used.
Frequently Asked Questions (FAQ)
- 1. What is the difference between nominal and actual board width for shiplap?
- Nominal width is the standard size name (e.g., 1×6), but the actual width is smaller after milling and the rabbet joint. The *actual coverage width* is even less because of the overlap. Always use the actual coverage width in the shiplap calculator.
- 2. How much extra shiplap should I buy?
- The calculator includes a wastage percentage. 10-15% is common, but for complex layouts or beginners, 15-20% might be safer.
- 3. Does this calculator work for vertical installation?
- Yes, the principle is the same. Just enter the wall width and height as they are. The number of boards and area remain the same regardless of orientation.
- 4. What if my boards come in different lengths?
- If you have mixed lengths, it’s best to calculate based on the most common length or calculate separately for batches of different lengths and sum the results, adjusting wastage.
- 5. How do I measure the actual coverage width?
- When two shiplap boards are interlocked, measure the width of one board that is exposed or visible.
- 6. Does the shiplap calculator account for gaps between boards?
- It assumes standard shiplap installation where boards fit snugly. If you’re intentionally leaving larger gaps (like a “nickel gap”), the coverage width of each board effectively increases slightly, but it’s usually minimal unless the gaps are very large.
- 7. Can I use this for tongue and groove paneling?
- Yes, if the tongue and groove also has an overlap that reduces the coverage width compared to the actual board width. Use the visible/coverage width in the shiplap calculator. Our tongue and groove calculator might be more specific.
- 8. What if my wall isn’t a simple rectangle?
- For L-shaped walls, calculate each rectangular section separately and add the results. For walls with gables, try to approximate the area or break it into rectangles and triangles, then adjust wastage upwards.