Use this workshop calculation to turn measured dimensions and the selected construction convention into a cut, spacing, fit, or material-planning value.

Board thickness (mm)

Board thickness in millimetres, between ten and sixty.

Recommend a batten spacing of 30 or 40 centimetres from the board thickness. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Batten spacing (cm)

Recommended batten spacing in centimetres.

• Nominal dimensions, kerf, moisture movement, hardware clearances, wall squareness, and manufacturer instructions can change the required shop dimension. Measure the actual assembly and test critical joints on scrap before cutting finished material.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Complement the calculated dimension with a physical story stick, dry fit, or full-size layout. Follow the hardware, coating, adhesive, or machine manufacturer's limits where they differ from a rule of thumb.

• Tread Thickness Rule

  Recommend a stair tread thickness of 40 millimeters for string spans up to 90 centimeters and 50 millimeters beyond.

• String Thickness Rule

  Recommend a stair string thickness of 45 millimeters for tread depths of 26 centimeters or more and 40 millimeters below.

• Cleat Width Rule Calculator

  Compute the cleat width as twice the panel thickness with a 30 mm minimum.