The drill size chart provides a list of standard size drill bits in several measurement systems, including fractional, metric, wire gauge number, and letter. The decimal equivalents of the diameters are shown in both English and Metric units. Fractional sizes are measured in inches, while metric sizes are measured in 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 drill size chart contains tools up to 1.5 inches in diameter, but larger tools are also commonly used.

Almost 75% of all elements are metals. Metals are used in electronics for wires and in cookware for pots and pans because they conduct electricity and heat well. Most metals are malleable and ductile and are, in general, heavier than the other elemental substances. Two or more metals can be alloyed to create materials with properties that do not exist in a pure metal.

All metals can be classified as either ferrous or non-ferrous. Ferrous metals contain iron and non-ferrous metals do not. All ferrous metals are magnetic and have poor corrosion resistance while non-ferrous metals are typically non-magnetic and have more corrosion resistance. An overview of the most common ferrous and non-ferrous metals is shown below.