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

Screw diameter (mm)

Outer thread diameter of the screw in millimeters.

Screw length (mm)

Full length of the screw in millimeters.

Compute pilot hole diameter and depth for a wood screw with 6 mm tip 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]

Pilot hole diameter (mm)

Pilot hole core-hole diameter in millimeters.

Pilot hole depth (mm)

Pilot hole depth in millimeters minus the 6 mm screw tip clearance.

• 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.

• Countersink Depth

  Calculate conical countersink depth between pilot-hole diameter and screw-head diameter from included countersink angle.

• Holzschraube Vorbohrung 07d

  Rule-of-thumb pilot diameter equal to 70% of a wood screw's outside diameter; adjust for screw and timber manufacturer guidance.

• 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.