Augmented Intervals

What is an augmented interval?

Augmented intervals are a half step wider than a perfect or major intervals.

For instance, if there is an interval a half step wider than a perfect 4th, we call it an augmented 4th. If there is an interval a half step wider than a major 6th, we call it an augmented 6th.

There is one caveat I need to point out. Wider does not mean higher in pitch. You can make an interval wider by lowering the lower end of the interval as well. Many students think there has to be a # to make an interval augmented, but the truth is sometimes it requires a #, and other times it requires a ♭.

As in the previous articles, I am attaching a diagram of a keyboard for your reference.

keyboard diagram

Augmented 2nd

When you widen a major 2nd by a half step, it will become an augmented 2nd.

C♮ to D#. C♮ to D♮ is a major 2nd. So by making it wider by a half step to a D#, it becomes an augmented 2nd. Notice that it is spelled a D#. If this is spelled an E♭, it is no longer an augmented 2nd, but it is now a minor 3rd. They sound the same, especially played on the piano, but they are two completely different intervals when it comes to music theory. This could be mind-boggling at first.

Example of augmented 2nd

A♭ to B♮. A♮ to B♮ is a major 2nd, so by extending the A♮ to an A♭, it becomes an augmented 2nd. Just like the example above, this would be a minor 3rd if the A♭ were spelled G#, sounds pretty much the same but completely different intervals in music theory.

Example of augmented 2nd

Augmented 3rd

When you widen a major 3rd by a half step, it will become an augmented 3rd.

F♮ to A#. F♮ to A♮ is a major 3rd. A# would widen the interval by a half step, making it an augmented 3rd.

Example of augmented 3rd

G♭ to B♮. G♮ to B♮ is a major 3rd. G♭ makes the interval a half step wider, so it becomes an augmented 3rd.

Example of augmented 3rd

Augmented 4th

When you widen a perfect 4th by a half step, it will become an augmented 4th.

C♮ to F#. C♮ to F♮ is a perfect 4th. When it is extended to a F#, it becomes an augmented 4th.

Example of augmented 4th

B♭ to E♮. B♮ to E♮ is a perfect 4th. Widen the interval by lowering it a half step to a B♭, and you get an augmented 4th.

Example of augmented 4th

Augmented 5th

When you widen a perfect 5th by a half step, it will become an augmented 5th.

C♮ to G#. C♮ to G♮ is a perfect 5th. Extend it to a G#, and now it is an augmented 5th.

Example of augmented 5th

D♭ to A♮. D♮ to A♮ is a perfect 5th. Extend it to a D♭, and it becomes an augmented 5th.

Example of augmented 5th

Augmented 6th

When you widen a major 6th by a half step, it will become an augmented 6th.

C♮ to A#. C♮ to A♮ is a major 6th. Widen it by a half step to A#, and you get an augmented 6th.

Example of augmented 6th

G♭ to E♮. G♮ to E♮ is a major 6th. When you widen it to G♭, it becomes an augmented 6th.

Example of augmented 6th

Now you know what augmented intervals are, let's move onto diminished intervals.