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

Core diameter (mm)

Screw core diameter in millimetres.

Penetration depth (mm)

Penetration depth in the wood in millimetres.

Wood group

Wood group: softwood (factor 0.8) or hardwood (factor 1.2).

Estimate screw pull-out resistance in kilograms from core diameter, penetration depth, and wood group. 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]

Pull-out resistance (kg)

Estimated pull-out resistance in kilograms.

• 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.

• Nail Withdrawal Estimate

  Estimate nail withdrawal resistance in kilograms from shank diameter, penetration depth, and wood group.

• Anchor Pull-Out Class Lookup

  Look up the rated pull-out load in kilograms for a metric anchor size.

• 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.