Plan an evenly spaced decorative wall
Board and batten treatment divides a wall into open bays separated by vertical strips of trim. This layout calculator begins with a strip at each end, then chooses enough intermediate strips that no clear bay exceeds your requested maximum. It solves for equal gaps rather than repeatedly marking a fixed distance and leaving an odd narrow opening at the far corner. The calculation is for decorative internal trim on one uninterrupted wall. It does not design structural wall members or weatherproof external cladding.
Separate clear gaps from centre spacing
Bays = ceil((wall width − batten width) ÷ (maximum gap + batten width)); battens = bays + 1After counting the battens, their combined face widths are subtracted from the wall. The remaining width is divided by the number of bays to give the equal clear gap. Adding one batten width gives centre-to-centre spacing. Metric wall measurements use metres and trim measurements use millimetres; imperial wall measurements use feet and trim measurements use inches. Actual face width matters: a nominal board label may not match the finished strip you intend to attach. The tool rejects a wall that cannot fit two end strips or a proposed bay layout with negative clear space.
Worked layout across a three-metre wall
A wall 3 metres wide is 3,000 millimetres across. With 50 millimetre battens and a maximum clear gap of 400 millimetres, the bay calculation is ceil((3,000 − 50) ÷ (400 + 50)) = 7. That means eight vertical strips, including the two ends. They occupy 400 millimetres together, leaving 2,600 millimetres for seven openings. Each opening is 371.43 millimetres wide and the centre spacing is 421.43 millimetres. At a vertical strip height of 1.2 metres, the net trim requirement is 8 × 1.2 = 9.6 linear metres before cutting losses.
Mark the layout before cutting
Draw both end strips on the wall or a scaled sketch before transferring centre marks. If the neighbouring wall already has a corner strip, decide whether it belongs inside your measured width and maintain that convention throughout. Doors and windows break the equal-bay pattern; calculate uninterrupted runs separately or adjust the layout on a drawing. Horizontal rails, cap mouldings, skirting and backing panels are excluded from the vertical trim result. Net linear length is not a stock-board purchase count, because kerf, defects and cut combinations can prevent every offcut from being useful. Dry-position strips or use removable marks to judge proportions, then confirm the actual gap fits the furniture, outlets and edges around the feature wall.
A reproducible calculation with complete inputs
For a reproducible board and batten spacing calculator example, use the metric input system and enter Wall width: 3 m; Actual batten width: 50 mm; Maximum clear gap between battens: 400 mm; Vertical batten height: 1.2 m. These settings describe one specific scenario, not a new default for every job. The result follows the method and allowances already explained above. Keep the entire set of values when comparing it with a hand calculation; omitting a selected material or an allowance can change the result even when the dimensions match. The following rows show the unrounded calculation values alongside the precision used by the interface.
| Result | Calculation value | Displayed value | Unit |
|---|---|---|---|
| Vertical battens | 8 | 8 | pieces |
| Equal clear gap | 371.428571429 | 371.43 | mm |
| Centre-to-centre spacing | 421.428571429 | 421.43 | mm |
| Vertical trim length | 9.6 | 9.60 | m |
| Number of open bays | 7 | 7 |
How should I prepare these entries?
Wall width: enter the value in m. Actual batten width: enter the value in mm. Maximum clear gap between battens: enter the value in mm. Vertical batten height: enter the value in m. Choose the unit system before transferring your measurements. A depth, length, area and coverage can have different field units even within one system. Read each label individually rather than entering the same unit convention in every box. Optional openings or allowances should describe your actual scenario instead of being silently left at a sample value. The worked inputs above identify exactly which selections produced the table.
How should I compare another measurement?
Change one measurement or option at a time and keep the other inputs fixed. The new result reflects the whole stated formula, including its conversions, allowances and purchase rounding. A quantity that depends on several dimensions does not necessarily respond linearly to every field. Compare intermediate area or volume outputs when present before interpreting the final rounded purchase quantity. This makes a misplaced unit easier to detect than judging the final total alone. Record the selected unit system beside each scenario so that a copied number is not silently reused under different field units.
Frequently asked questions
Are end battens included?
Yes. The count includes one full-width vertical strip at each end and all intermediate strips required for the equal-bay layout.
What does maximum clear gap mean?
It is the largest open distance between adjacent batten faces. The final equal gap can be smaller because the number of bays must be an integer.
Is centre spacing the same as the opening?
No. Centre spacing equals clear gap plus one actual batten width. Use the displayed value that matches how you make your marks.
Does this count horizontal rails?
No. Vertical trim length includes only the upright pieces at the entered height. Add rails, caps, backing and cutting losses separately.
How should I handle a door?
Treat uninterrupted sections individually or draw a full elevation. This simple layout has no openings and cannot align trims around door or window edges automatically.