The note value allows us to specify the duration of a sound. In the example below you can see the note values and their duration:

Note	Name (USA)	Name (England)	Value
	Double Whole Note	Breve or brevis	Two whole notes
	Whole Note	Semibreve	Two Half Notes or a half of a Double Whole Note
	Half Note	Minim	Two Quarter Notes or a half of a Whole Note
	Quarter Note	Crotchet	Two Eighth Notes or a half of a Half Note
	Eighth Note	Quaver	Two Sixteenth Notes or a half of a Quarter Note
	Sixteenth Note	Semiquaver	Two 32nd Notes or a half of an Eighth Note
	32nd Note	Demisemiquaver	Two 64th Notes or a half of a Sixteenth Note
	64th Note	Hemidemisemiquaver	Half of a 32nd Note
Names in other languages

As you can see, each note is twice as long as the following note and half as long as the previous one.

NOTE: When we write eighths, sixteenths, thirtieths, and sixty-fourths, we usually group all notes within a "family" (note type) with a bar to make them easier to read:

---

---