Shiplap Measurement: How to Measure and Calculate Shiplap for Perfect Wall Installation
Planning a shiplap wall project? Before you grab the boards and start nailing, accurate shiplap measurement is the key to success. Measuring correctly ensures you buy the right amount of material, avoid waste, and achieve the professional look that makes shiplap so popular.
Whether you’re designing a cozy farmhouse-style accent wall or covering an entire room, understanding how to measure, calculate, and plan your shiplap layout will save time, money, and frustration.
What Is Shiplap Measurement and Why It Matters
Shiplap measurement refers to the process of determining the total area of your wall and calculating how much shiplap material you need to cover it.
Because shiplap boards have overlapping grooves (known as a “rabbet joint”), you can’t simply measure your wall and buy an equal number of square feet in planks. The overlapping edges reduce coverage per board, which is why precise measurement is essential.
Getting the measurement right prevents:
- Wasting money on excess boards.
- Running short on material halfway through installation.
- Misaligned boards that throw off your pattern.
Accurate shiplap measurement ensures a seamless installation, clean horizontal or vertical lines, and a balanced aesthetic across your space.
How to Measure Your Wall for Shiplap
To measure for shiplap, you’ll need a tape measure, notepad, pencil, and a calculator.
Here’s a step-by-step guide to ensure every inch is accounted for.
Step 1 – Measure Wall Width and Height
Start by measuring the width and height of your wall in feet. Multiply those numbers to get the total square footage.
Formula:Wall Width × Wall Height = Total Wall Area
For example, if your wall is 12 feet wide and 8 feet tall:12 × 8 = 96 square feet
Write this number down — it represents the total surface area you’ll be covering with shiplap.
If your wall has windows, doors, or built-in shelves, measure those areas separately and subtract them from your total wall area.
Formula:Total Wall Area – (Window Area + Door Area) = Net Wall Area
Example:96 – (10 + 15) = 71 square feet
Step 2 – Determine Board Coverage Area
Every shiplap board covers a certain amount of space once installed. This depends on the width of the board and its effective exposed width (after accounting for the overlap).
For instance, a 1×6 shiplap board usually covers around 5 inches of width once installed.
Formula:(Exposed Width in Inches ÷ 12) × Board Length (in Feet) = Coverage Area per Board
Example:(5 ÷ 12) × 8 = 3.33 square feet per board
That means each 8-foot board covers roughly 3.33 square feet.
Step 3 – Calculate the Number of Boards Needed
Now divide your total wall area by the coverage area per board.
Formula:Total Wall Area ÷ Coverage Area per Board = Boards Needed
Example:71 ÷ 3.33 = 21.3 boards
Always round up to the next full board since you can’t buy a fraction of one.
Step 4 – Add 10–15% for Waste and Cuts
During installation, you’ll lose some material to cuts and fitting adjustments. Professionals typically recommend buying 10–15% extra.
Formula:Boards Needed × 1.10 (or 1.15) = Total Boards to Purchase
Example:21.3 × 1.10 = 23.43 → 24 boards total
Having extra boards ensures you’re prepared for mistakes, warped pieces, or pattern adjustments.
Step 5 – Mark and Plan Your Layout
Mark your wall horizontally (or vertically if installing that way) using a level and pencil. This helps maintain consistent spacing and alignment.
You can use spacers — like a nickel or tile wedge — to create uniform gaps between boards. A small consistent gap provides that signature shiplap look.
To maintain balance, plan the first and last boards carefully. It’s better to cut both ends evenly than to end up with a thin strip at the top or bottom.
Common Shiplap Sizes and Their Impact on Measurement
Not all shiplap boards are created equal. Sizes vary by manufacturer and style, and each affects your measurement and final appearance.
Here’s a simple table showing standard sizes and coverage area per 8-foot board:
| Nominal Size | Actual Exposed Width | Length (ft) | Coverage Area per Board (sq ft) |
|---|---|---|---|
| 1×4 | 3.25 inches | 8 | 2.17 |
| 1×6 | 5 inches | 8 | 3.33 |
| 1×8 | 6.75 inches | 8 | 4.50 |
| 1×10 | 8.75 inches | 8 | 5.83 |
Wider boards mean fewer seams and faster installation but may show more wood movement with temperature changes. Narrow boards create a more traditional or detailed look but require more cuts.
When measuring, always use the actual exposed width (not the nominal board width), since that determines coverage.
Vertical vs Horizontal Shiplap Measurement
Most installations use horizontal shiplap, but vertical designs are increasingly popular for accent walls.
Horizontal Installation
- Measure width × height as shown above.
- Use board coverage area to calculate total boards.
- Plan for symmetrical cuts at top and bottom.
Vertical Installation
- Measure wall height (this becomes your board length).
- Measure wall width to calculate how many boards fit side by side.
- Add spacing between boards (usually 1/8 inch).
Formula for Vertical Layout:(Wall Width ÷ (Exposed Board Width + Gap)) = Number of Boards Needed
For example:144 ÷ (5 + 0.125) = 28.13 boards
You’d need about 29 boards across for a 12-foot wall.
Vertical layouts use slightly more material due to the small gaps and trim work.
Shiplap Measurement Tips for Accuracy
- Measure at multiple points. Walls and ceilings are rarely perfectly square; measure width and height at least three points to find the average.
- Always round up. It’s safer to have extra material than run short.
- Account for trim and outlets. Measure carefully around windows, doors, and power outlets.
- Use a level for every row. Shiplap highlights crooked lines.
- Plan your pattern. Some homeowners prefer symmetrical top and bottom boards for aesthetics.
- Dry fit first. Lay a few boards on the floor to visualize the pattern before nailing.
- Label each cut. When cutting multiple pieces, label them (A1, A2, etc.) for easier installation.
For help measuring awkward spaces or corners, check out our Ladder Angle Calculator to ensure safe access while working at heights.
Shiplap Cost and Material Estimation
After measuring, you can easily estimate cost.
Formula:Total Square Footage × Cost per sq ft = Estimated Total Cost
Example:96 sq ft × $2.50 = $240
Average shiplap prices range from $1.50 to $3.50 per square foot, depending on material type (pine, MDF, PVC, etc.).
If you’re covering multiple walls, calculate each wall separately and add totals together.
For large rooms or remodels, our Paint Calculator and Flooring Calculator are helpful for estimating overall project materials.
Orientation, Spacing, and Finishing Touches
1. Orientation
- Horizontal: Classic farmhouse style, visually widens the room.
- Vertical: Adds height, great for accent walls.
- Diagonal: Trendy, but requires precise cutting and angles.
2. Spacing
Most shiplap boards use a 1/8-inch gap (nickel gap). Use spacers to maintain consistency.
3. Finishing
Once installed, fill nail holes, sand lightly, and apply paint or stain. For flawless results, use semi-gloss or satin paint for easy cleaning.
Advanced Tips for Precision and Efficiency
- Use a digital laser measure for long walls.
- Measure twice, cut once — the oldest and best carpentry advice.
- Check moisture levels of boards before installation; wood expands and contracts.
- Plan electrical adjustments early. If outlets or switches interfere with boards, plan cutouts ahead.
- Account for wall irregularities. Older homes may have bowed walls; use trim to hide small imperfections.
If your project involves building custom spaces like greenhouses or sheds, you can also use our Hoop House Calculator to determine framing and spacing for curved structures.
Environmental Considerations
Choosing sustainable shiplap materials can improve your project’s longevity and reduce environmental impact. Opt for FSC-certified wood or recycled composites.
For example, the Modern Mill ACRE product line uses upcycled rice hulls for durable, eco-friendly shiplap alternatives — read more here (Outbound link).
Common Measurement Mistakes to Avoid
- Ignoring overlap – Always calculate exposed width, not nominal width.
- Skipping waste factor – Cutting waste averages 10–15%.
- Forgetting gaps – Leave expansion space at wall edges.
- Not checking level lines – Crooked boards multiply as you go up the wall.
- Assuming all boards are straight – Check each piece before installation.
These small details make a huge difference in achieving a professional look.
Related Tools for Accurate Measurement
For projects beyond shiplap, you can use other helpful tools to ensure perfect results across your renovation:
- Paver Calculator – For outdoor patios.
- Paver Sand Calculator – To estimate base materials.
- Ramp Calculator – For accessibility projects.
- Furnace Size Calculator – For HVAC planning.
- Heat Loss Calculator – For energy efficiency.
- Plywood Calculator – For wall backing or underlayment.
These tools simplify measurement-based planning, just like the Shiplap Calculator designed specifically for this guide.
Proper shiplap measurement transforms a DIY project from guesswork into precision. By using simple formulas and allowing for overlap, gaps, and waste, you can determine exactly how much material you need for a flawless installation.
Measure carefully, plan your layout, and choose the right board size for your style. Whether you’re covering a feature wall, a ceiling, or an entire room, accuracy is the foundation of craftsmanship.
Once you’ve measured your walls, try our Shiplap Calculator to double-check your numbers and ensure you order the perfect amount of material.