Augmented fifth
| Inverse | diminished fourth |
|---|---|
| Name | |
| Other names | - |
| Abbreviation | A5 |
| Size | |
| Semitones | 8 |
| Interval class | 4 |
| Just interval | 25:16 |
| Cents | |
| Equal temperament | 800 |
| 24 equal temperament | 800 |
| Just intonation | 773 |
In classical music from Western culture, an augmented fifth (
Play ) is an interval produced by widening a perfect fifth by a chromatic semitone. For instance, the interval from C to G is a perfect fifth, seven semitones wide, and both the intervals from C♭ to G, and from C to G♯ are augmented fifths, spanning eight semitones. Being augmented, it is considered a dissonant interval.
Its inversion is the diminished fourth, and its enharmonic equivalent is the minor sixth.
The augmented fifth only began to make an appearance at the beginning of the common practice period of music as a consequence of composers seeking to strengthen the normally weak seventh degree when composing music in minor modes.
This was achieved by chromatically raising the seventh degree (or subtonic) to match that of the unstable seventh degree (or leading tone) of the major mode (an increasingly widespread practice that led to the creation of a modified version of the minor scale known as the harmonic minor scale).
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