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

Biscuit Width Millimeters (mm)

Required number input.

Glue Clearance Millimeters (mm)

Required number input.

Target insertion depth on each side of a centered biscuit joint from biscuit width plus a chosen glue clearance. 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]

Slot Depth Millimeters (mm)

The resulting slot 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.

• Dowel Hole Depth

  Size each equal dowel hole for a centered dowel plus end clearance on that side.

• Dowel Drill Depth Calculator

  Compute the blind-hole depth in each half of a centered dowel joint as half the dowel length plus 2 mm of glue and chip clearance.

• Domino Depth

  Equal mortise depth in each member for a centered floating tenon, plus a specified glue-relief allowance.