The Types of Intervals

Perfect Consonances Imperfect Consonances
Perfect Unison (P1, PP) Minor Third (m3)
Perfect Fourth (P4) Major Third (M3)
Perfect Fifth (P5) Minor Sixth (m6)
Perfect Octave (P8) Major Sixth (M6)
Diatonic Dissonances Chromatic Dissonances
Minor Second (m2) Augmented Second (A2, +2)
Major Second (M2) Augmented Sixth (A6)
Minor Seventh (m7) Diminished Third (d3)
Major Seventh (M7) Diminished Fourth (d4)
Tritone (A4, +4, d5, °5, T, TT) Any Other Augmented
or Diminished Interval