List of Drill Bit and Tap Sizes – Drill Size Chart and Tap Size Chart

Drilling is an important process of producing a hole while tapping is a technique used to cut a thread inside a hole, both the drill bit and the tapping tool are often used in producing custom cnc machining parts with thread holes. In this case, we should refer to the standard drill and tap size chart.

The drill size chart is a table, which lists all the standard size drill bits in several measurement systems, including fractional, metric, wire gauge number, and letter. The unit of the Fractional sizes is inch, and the unit of the metric sizes is millimeters. The wire gauge and letter systems refer to tool diameters that increase as the wire gauge decreases from #107 to #1 and then continues from A to Z. The decimal equivalents of the diameters are shown in both English and Metric units.

The tap size chart is a table, which lists the standard size taps, specifying the diameter and thread spacing, for fractional and metric. Fractional sizes are listed in inches and metric sizes are listed in millimeters, which were followed by the letter "M". In the fractional and screw size systems, the numbers of the thread are measured per inch, such as UNF threads and UNC threads.  

List of Drill and Tap Sizes

Drill Bit Sizes (Metric)

The drill size chart contains tools up to 1.5 inches in diameter, but larger tools are also commonly used.

Drill Bit Sizes (English)

Tap Sizes (Metric)

For each thread count, the equivalent thread pitch is provided and for metric taps, the approximate thread count is shown based on the pitch. Lastly, the recommended tap drill size is provided for each standard tap size. This size drill bit should be used for drilling the initial hole that will then be tapped.

Tap Sizes (English)