There are two forms of key styles used today, 'closed hole' keys and the open hole style. The open hole flutes have five keys which have holes in them -the A key, one of the G keys, the F, E and D keys. The purpose of the hole is to provide increased air circulation when the key is open. To close the key, the finger must cover the hole completely. In addition to the acoustical differences for this key style, there are certain artistic and aesthetic preferences for them, as well as the ability to encompass many of the modern day flute techniques which may require the player to half cover the key hole.

The most common key style in the U.K is the closed hole version which as the name implies, has keys without holes.