Augmented fifth

The musical interval of an Augmented fifth is. It is the inversion of the diminished fourth, and in twelve tone equal temperament is enharmonically equal to a minor sixth.

The Augmented fifth is the largest interval in the Augmented chord. It can be produced by starting on a high note and playing the fifth below or by starting on a low note and playing the fifth above.

In an equal tempered tuning, an Augmented fifth is equal to eight semitones, a ratio of 1:2^8/12 (approximately 1.587), or 800 centss.

In the common practice period augmented fifths were considered dissonant or unstable and disallowed.