About Tap-and-Clearance

Tap-and-Clearance is a free reference for tap drill and clearance hole sizes. It was built by an engineer who wanted a faster way to look up drill sizes than digging through PDF charts.

Each size page lists the recommended tap drill for soft and hard materials, close and free fit clearance holes, and the decimal size of every drill. You can also print a shop chart in inch or metric.

Tap drill sizes are based on standard thread engagement: about 75% for aluminum, brass, and plastics, and about 50% for steel, stainless, and cast iron. They cover Unified (UNC/UNF) and ISO metric threads. Use them as a starting point for general shop work, and check your tap manufacturer's recommendations for critical parts.

Found an error or want a size added? Get in touch through the contact section.