Screw Length & Pilot Hole Calculator

How to use these calculators

For screw length: enter your top (attached) piece thickness and the base material’s thickness — the range accounts for penetrating anywhere from half to nearly the full base thickness, which covers most general fastening. For pilot holes: pick your screw gauge and whether you’re driving into softwood or hardwood, since hardwood needs a slightly larger pilot to avoid splitting.

Why pilot holes matter

A pilot hole that’s too small doesn’t prevent splitting — it just makes the screw harder to drive and more likely to snap. Too large and the screw won’t grip. The right size lets the threads bite without fighting the wood’s grain.