Shiplap Calculator · Boards, Coverage & Cost

Shiplap Calculator

Estimate boards, rows, linear length and total cost for any shiplap wall

Wall Dimensions
Board Specifications
Face width = the visible width of each board after installation · Reveal / overlap = how much the boards overlap (reduce exposed face) · Gap = optional space between boards (usually 0 for shiplap).
Waste & Pricing
%
Shiplap Estimate
✅ Ready to Install
Boards Needed (with waste)
—
—
Wall Area
—
Rows / Columns
—
Total Linear Length
—
Total Cost
—
📋 Project Summary
Enter the wall and board dimensions to see the estimate.
Boards (No Waste)
—
Effective Face Width
—
Coverage per Board
—
Waste Allowance
—
🧾 Material Summary
Item
Quantity
Detail
Shiplap Boards
—
—
Boards (no waste)
—
—
Wall Area
—
—
Total Cost
—
—
📊 Common Shiplap Board Sizes
Nominal Size
Face Width
Typical Use
1×4
~8.9 cm (3.5 in)
Fine detail, small accent walls.
1×6
~14 cm (5.5 in)
Most common shiplap look.
1×8
~18.4 cm (7.25 in)
Wider, modern farmhouse style.
1×10
~23.5 cm (9.25 in)
Bold look, fewer rows.
1×12
~28.6 cm (11.25 in)
Very wide, rustic panels.
Estimate only. Actual board counts may vary with wall framing, outlets, corners and pattern. Add extra for openings (doors, windows) or complex layouts.

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Faiq Ur Rahman

Founder & CEO, Toolraxy

Faiq Ur Rahman is a web designer, digital product developer, and founder of Toolraxy, a growing platform of web-based calculators and utility tools. He specializes in building structured, user-friendly tools focused on health, finance, productivity, and everyday problem-solving.

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What Is Shiplap?

Shiplap is a timber board with a rabbeted edge, a small step cut into the top and bottom (or sides, if vertical) so adjacent boards overlap and sit flush. That joint creates the characteristic shadow line and helps the wall resist moisture movement.

Shiplap looks deceptively simple on a finished wall evenly spaced boards, tight reveals, a clean horizontal rhythm. Behind that calm surface sits a set of decisions that determine how much material you actually need: how wide is each board’s exposed face, how much do the edges overlap, are the boards running with or against the wall’s dimensions, and how much waste should you budget for cuts and mistakes? Get one of those wrong and you either run short mid-install or end up storing half a pallet in the garage. This shiplap calculator turns those decisions into a firm board count and a cost figure. It is built for homeowners planning an accent wall, carpenters pricing a job, and anyone trying to work out whether a particular board width will give them the look they want without ordering far more timber than the wall can use.

 

How to Use the Shiplap Calculator

  1. Type the wall’s Width into the first field and select the matching unit from the dropdown.

  2. Enter the wall’s Height the same way. The Wall Area field fills in automatically.

  3. Choose whether the boards will run Horizontal or Vertical using the radio buttons.

  4. Enter the Board Face Width, the visible width of one board once installed, not the nominal size.

  5. Add the Board Stock Length you plan to buy, typically 2.4 m or 8 ft.

  6. If your boards overlap, enter the Reveal / Overlap so the effective face is calculated correctly.

  7. Set a Waste Allowance percentage, usually 10% for a simple rectangular wall.

  8. Pick a pricing basis, select your currency, enter the price, and read the total cost tile at the bottom.

 

How the Shiplap Calculator Formula Works

The calculator builds up the answer in stages. First it works out the wall area, then the effective face width of each board after any overlap, then how many boards fit across the wall, then the total linear length those rows or columns represent. Finally it converts that length into whole boards using your stock length and adds the waste allowance.

Formula: Wall Area = Wall Width × Wall Height
Formula: Effective Face = Board Face Width − Overlap
Formula: Pitch = Effective Face + Gap
Formula: Rows (horizontal) = ceil(Wall Height ÷ Pitch)
Formula: Columns (vertical) = ceil(Wall Width ÷ Pitch)
Formula: Total Linear Length = Rows × Wall Width (horizontal)
= Columns × Wall Height (vertical)
Formula: Boards (no waste) = ceil(Total Linear Length ÷ Board Stock Length)
Formula: Boards (with waste) = ceil(Boards × (1 + Waste% ÷ 100))
Formula: Coverage per Board = Effective Face × Board Stock Length

Two validation rules matter. Wall width and height must both be greater than zero, and the effective face must stay positive, if the overlap you enter is equal to or larger than the board’s face width, the calculator refuses to produce a result rather than showing a misleading figure. Negative gap or overlap values are treated as zero.

 

Worked Example

A homeowner is cladding a 3.2 m × 2.4 m chimney breast in horizontal shiplap using 1×6 boards with a 14 cm face width, bought in 2.4 m lengths, with a 10% waste allowance.

  • Wall area = 3.2 × 2.4 = 7.68 m²

  • Effective face = 14 cm − 0 cm = 0.14 m

  • Pitch = 0.14 m (no gap for shiplap)

  • Rows = ceil(2.4 ÷ 0.14) = 18 rows

  • Total linear length = 18 × 3.2 = 57.6 m

  • Boards (no waste) = ceil(57.6 ÷ 2.4) = 24 boards

  • Boards (with 10% waste) = ceil(24 × 1.10) = 27 boards

  • Coverage per board = 0.14 × 2.4 = 0.336 m²

The takeaway: a 7.68 m² wall consumes around 24 boards before waste, and the extra three boards cover cuts at the wall edges and any miscuts. If you switched to 1×8 boards at 18.4 cm face width, the row count would drop to 14 and the total linear length to roughly 44.8 m noticeably fewer boards, but a wider reveal that changes the visual rhythm of the finished wall.

Frequently Asked Questions

How many shiplap boards do I need for a wall?

Divide the wall’s height by the board’s effective face width to get the row count, multiply by the wall width for total linear length, then divide by the board stock length and round up. Add 10% for waste on a simple rectangular wall.

 

What is the difference between board face width and nominal size?

Nominal size is the rough sawn dimension, such as 1×6. Face width is the actual visible width after milling, which for a 1×6 is roughly 14 cm or 5.5 in. Shiplap calculators must use the face width, or the row count will be wrong.

 

Does board orientation change how many boards I need?

Yes. Running boards horizontally means the row count depends on wall height, while running them vertically means the column count depends on wall width. On a wide, short wall, vertical boards often use fewer stock lengths because each board runs the shorter distance.

 

How much waste should I allow for shiplap?

Ten percent is a sensible default for a rectangular wall without openings. Increase to 12–15% if the wall has windows, doors, sockets, or irregular corners, or if the boards will be cut at angles. Waste allowances above 15% are rarely justified and usually indicate an overly complex layout.

 

Can I install shiplap vertically?

Yes. Vertical shiplap has become increasingly popular for feature walls and fireplace surrounds. The calculator handles it by swapping the row and column logic, using wall height as the length of each board and wall width as the dimension to divide by the pitch.

 

What does the reveal or overlap field do?

It reduces the effective face width of each board. If a board has a 14 cm face and you enter a 2 cm overlap, the calculator treats each board as covering 12 cm of wall. In standard shiplap installation the overlap is usually zero because the rabbeted joint is designed to sit flush.

 

Is the gap between boards normally zero for shiplap?

Yes. Shiplap’s defining feature is its tight, closed joint. A gap is occasionally used for a more rustic look or to allow ventilation behind the cladding, but it is not standard and will increase the number of rows required.

 

Why does the calculator round board counts up?

You cannot buy a fraction of a board, and cutting a board down to fit does not reduce the number you need to purchase. Always rounding up guarantees you have enough material; rounding down means a mid-project shortage.

 

What wall area does one board cover?

Multiply the effective face width by the board’s stock length. A 14 cm face board in a 2.4 m length covers 0.336 m² of visible wall. That figure is useful for cross-checking the total against the wall area.

 

Can I use this calculator for other cladding types?

The geometry applies to any board-based wall cladding, tongue and groove, shou sugi ban, or plain timber battens as long as you know the effective face width and the stock length. The overlap field lets you adapt it to profiles that rely on a rebate.

 

What is the most common shiplap board width?

1×6, with a face width of roughly 14 cm (5.5 in), is by far the most common in residential work. It strikes a balance between visual interest and installation effort. Wider boards cover more area per row but need a larger wall to look proportionate.

Disclaimer

This shiplap calculator provides an estimate based on the wall dimensions, board specifications and pricing you enter. Actual board counts can vary with wall framing irregularities, openings, corner details, pattern matching and the cutting plan your installer follows. Always order a small contingency beyond the calculated figure, and confirm board face widths and stock lengths with your supplier before purchasing, since nominal sizing varies between manufacturers and between dressed and rough-sawn stock.

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