**Simple intervals** are not larger than an octave, while **compound intervals** are larger than an octave. Ninths, tenths, elevenths and thirteenths are examples of compound intervals. Octaves, thirds and fifths are simple intervals.

Every compound interval is related to a simple interval. If you subtract 7 from a compound interval, you get the corresponding simple interval. For example, 9 - 7 = 2, so a ninth is related to a second. A compound interval has the same quality as the simple interval to which it is related. Here are some examples of compound intervals and their related simple intervals:

See Reading Music in the Tutorials section.