Pocket Hole Calculator — Screw Size and Spacing

Screw length depends on material thickness: 25mm screws for 12–15mm stock, 32mm for 18mm stock, 38mm for 22–25mm stock, 50mm for 32mm stock, and 64mm for 38mm stock. Always use screws designed for pocket hole jigs — they have a flat head and self-tapping tip.

For face frames, space pocket holes 150mm apart. For panel joints, 200–250mm is adequate. For structural joints, reduce spacing to 100mm. Always place a hole within 50mm of each end.

Use COARSE thread for softwoods (pine, spruce, cedar, fir, poplar) and for all sheet goods (plywood, MDF, particleboard, melamine) — the aggressive thread bites the soft or loose fibres and grips them. Use FINE thread for dense hardwoods (oak, maple, cherry, birch, ash, walnut, mahogany) to avoid splitting. This follows Kreg’s screw-selection guidance.