MT Intervals

1 semitone

m2

2 semitones

M2

3 semitones

m3

4 semitones

M3

5 semitones

perfect 4th

6 semitones

tritone/diminished 5/augmented 4

7 semitones

perfect 5

8 semitones

m6

9 semitones

M6

10 semitones

m7

11 semitones

M7

12 semitones

perfect octave

Harmonic Interval

Simultaneous interval

Melodic interval

one after the other

Do accidentals count when determining size?

No

Simple interval

Smaller than octave

Compound interval

Bigger than octave

2nds, 3rd, 6ths, 7ths

Major or Minor

Minor shrinks by semitone

diminished

Major grows by semitone

augmented

Inversion

Swap upper/lower notes by octave

Enharmonic intervals

Different sizes, same number of semitones

Consonant

Stable. Beg. and end of pieces

Dissonant

Unstable. Moves music forward.

Perfect consonances

Perfect unisons, perfect 5ths, perfect octaves

Imperfect consonances

Major and minor 3rds and 6ths

When 2 intervals are enharmonic

One is always dissonant