The major scale can be seen as degrees. If the 1st degree is C, the 5th degree is G. C to G is a perfect 5th, which is an INTERVAL. An interval is the distance between two notes.

1. The Major ScaleThe_Major_Scale.html
3. Relative and ParallelRelative_and_Parallel.html
4. Intro to ModesIntro_to_Modes.html
5. Other ScalesOther_Scales.html





in C

Number of

Half Steps

Diminished 5ths are the same as Augmented 4ths. DIMINISHED shortens something, and AUGMENTED raises. The Dim 5th is also know as the TRITONE; named for three tones (whole steps)

augmented 4th

One way to calculate an interval is to actually count the half steps, which you could then compare to the chart above.

In the case to the right, QUALITY is decided by having either a C or a C#. C# is further away, which would mean it is the bigger interval. C is closer, so we see it’s a min 6th.



when you count the NUMBER,

you always count inclusive

An inversion is taking one of the two notes of an interval, and moving it an octave up or down (towards the other note).


when inverted, P5 intervals become P4s

and vice versa

Why is it called  a Perfect 5th and Perfect 4th? In a time before mathematics could explain such things, musicians noticed that the intervals we call perfect 4th and 5th we’re different from the rest in sound, and they knew this solely by ear. The P5 has the least clash in pitch with the root, making it very stable. And the P4 is simply P5 inverted.

ALL P5 intervals, no matter what pitches, will make a 3/2 ratio. 3/2 is a very simple ratio. As intervals get more dissonant, the ratios get more complicated.

maj becomes min,

2nds becomes 7ths,

3rds become 6ths -

vice versa for all.

Perfect Unison becomes Perfect octave

Dim 5ths stays the exact same.

659.2 hz ≈ 660 hz

440 hz

and ParallelRelative_and_Parallel.html