Shiplap Calculator
Estimate how many shiplap boards you need for your wall or project.
Estimate how many shiplap boards you need for your wall or project.
What This Shiplap Calculator Does
This calculator estimates the number of shiplap boards required to cover a wall or project surface. You input your wall dimensions and board specifications, and it returns the total board count, accounting for standard overlap and spacing.
It eliminates manual measurement guesswork, helping you order the right amount of material before starting your installation.
How the Calculation Works
The calculator uses your wall height and width, along with the board width and the gap (or overlap) between boards, to determine how many boards fit horizontally across the wall.
The core logic is:
- Effective board coverage = board width + gap (or overlap)
- Number of boards = wall width ÷ effective coverage
- Result is rounded up to the nearest whole board
If you specify a waste factor (e.g., 10%), the calculator adds extra boards to account for cuts, mistakes, or irregular wall features.
How to Use the Calculator
- Measure your wall height and width in inches or feet.
- Enter the width of one shiplap board (typically 5.5 or 7.25 inches).
- Set the gap or overlap between boards (commonly 0 for tight fit, or 1/8 inch for spacing).
- Optionally add a waste percentage (5–10% is standard).
- Click calculate to see the total boards needed.
Example Calculation
Suppose you have a wall that is 10 feet wide (120 inches) and you are using 5.5-inch shiplap boards with no gap.
- Effective coverage per board: 5.5 inches
- Boards needed: 120 ÷ 5.5 = 21.8 → 22 boards
- With 10% waste: 22 × 1.1 = 24.2 → 25 boards
This means you would order 25 boards to have enough material for cuts and adjustments.
Understanding Your Results
The output shows the minimum number of boards required to cover the wall surface. This does not account for complex patterns, angled cuts, or non-rectangular wall sections.
If your wall has windows, doors, or outlets, you may need fewer boards than the estimate suggests. The waste factor helps compensate for these variations.
Common Mistakes to Avoid
- Forgetting the gap: If you plan to leave a small gap between boards, include it in the calculation or your estimate will be too low.
- Ignoring waste: Even experienced installers need extra material for cuts and mistakes. Always add at least 5–10%.
- Measuring in different units: Keep all measurements in the same unit (inches or feet) to avoid calculation errors.
- Not accounting for board length: This calculator assumes boards run the full height of the wall. If you need to join boards vertically, adjust your estimate accordingly.
Limitations of This Calculator
This tool provides a linear estimate based on wall width and board coverage. It does not account for:
- Vertical board installation (boards running horizontally)
- Non-rectangular walls (sloped ceilings, arches)
- Board length constraints (if boards are shorter than wall height)
- Pattern layouts (herringbone, diagonal)
For complex installations, consult a professional or create a detailed layout plan before ordering materials.
Practical Use Cases
- Accent walls: Quickly estimate material for a single feature wall in a living room or bedroom.
- Bathroom wainscoting: Calculate boards needed for a half-wall shiplap installation.
- Ceiling shiplap: Use the same method to estimate boards for a ceiling project.
- Budget planning: Get a board count to compare material costs across different board widths and suppliers.
FAQ
What is the standard shiplap board width?
Common widths are 5.5 inches and 7.25 inches, but boards can range from 3 to 12 inches depending on the manufacturer and style.
Do I need to account for the tongue and groove?
Yes. The effective coverage of each board is slightly less than its total width due to the tongue-and-groove joint. Most calculators, including this one, let you set the gap or overlap to account for this.
How much waste should I add?
5–10% is standard for simple rectangular walls. Add 15% or more for walls with many obstacles, angles, or if you are a beginner.
Can I use this for horizontal shiplap installation?
This calculator assumes vertical board installation (boards running top to bottom). For horizontal installation, swap the height and width inputs.
What if my wall has windows or doors?
The calculator gives a rough estimate. For accurate material ordering, subtract the area of openings from your total wall width or use a detailed layout plan.