Board and Batten Calculator

Lay out evenly spaced battens

Enter the wall width, actual batten width, desired clear gap, and batten height in inches. Choose whether a batten or an equal gap sits at each end. The result gives a whole batten count, adjusted spacing, and left-edge marks measured from the same left wall.

Clear gaps and board widths

The clear gap is the visible opening between neighboring battens. It is different from center-to-center spacing, which includes one batten width. Measure the actual trim face rather than its nominal lumber size. Baseboards, corner trim, and existing casing may reduce the width available for your layout, so measure between the boundaries where this pattern will start and stop.

How the count is selected

With battens at both ends, the tool divides wall width minus one batten by the desired gap plus batten width. It rounds that interval count to the nearest whole number and adds one batten. The remaining wall width is shared equally among the gaps. With gaps at both ends, there is one more gap than batten; the same repeating-width approach chooses a nearby whole count. The actual gap may differ from your target.

Worked example: a ten-foot wall

For a 120-inch wall, 3-inch battens, and a desired 24-inch gap, choose battens at both ends. Five battens use 15 inches, leaving 105 inches for four gaps. Each gap is 26.25 inches. Left edges fall at 0, 29.25, 58.5, 87.75, and 117 inches. Five 48-inch battens total 20 linear feet before waste, rails, and cut allowances.

Use the marks without accumulating error

Measure every mark from the same origin instead of repeatedly measuring from the last installed batten. The download lists the marks for reference. Displayed values round to three decimal places, but the calculation uses unrounded spacing. The preview shows horizontal spacing to scale; its fixed height makes narrow strips visible and does not represent the actual batten height.

Assumptions and limitations

This is an interior decorative-layout estimate. It does not design structural siding, fasteners, ventilation, or building connections. Windows, outlets, uneven corners, and multiple adjoining walls may require a different count or deliberate asymmetry. Stock-board cuts, horizontal rails, defects, and waste are excluded from the linear footage. Layouts above 500 battens are rejected to keep the marks and drawing usable.