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

Tenon insertion length (mm)

Required number input.

End clearance (mm)

Required number input.

Specify mortise depth for a given tenon length plus a deliberate end-clearance allowance for glue or debris. 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]

Required mortise depth (mm)

The resulting required mortise depth 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.

• Domino Depth

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

• Tenon Length

  Find maximum tenon insertion length from measured mortise depth after reserving a nonnegative end clearance.

• 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.