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

Stock Thickness Millimeters (mm)

Required number input.

Cut depth for a centered half-lap joint in a board of uniform 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]

Cut Depth Millimeters (mm)

The resulting cut depth millimeters returned as a number.

• 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.

• Half-Lap Cross Joint Calculator

  Compute the lap thickness and cut depth that halve a cross-lapped board.

• Box Joint Depth

  Size box-joint fingers from mating board thickness plus deliberate protrusion before flushing.

• Domino Routing Depth Calculator

  Compute the mortise depth for a centered Domino loose-tenon joint. Each workpiece normally receives half the nominal tenon length; verify the joiner's available depth-stop setting, especially for the 4 x 20 mm Domino.