Inverting intervals

You invert an interval when you move the lowest tone of an interval one octave higher or the highest tone one octave lower. The general name changes this way:

• Second becomes seventh.
• Third becomes sixth.
• Forth becomes fifth.
• Fifth becomes fourth.
• Sixth becomes third.
• Seventh becomes second.

The specific name changes this way:

• Diminished becomes augmented.
• Minor becomes major.
• Perfect stays perfect.
• Major becomes minor.
• Augmented becomes diminished.

Below are two examples, a major third is inverted and becomes a minor sixth, and a minor seventh is inverted and becomes a major second.

Figure 3.12.