Intervals
Augmented Seventh
7A · 12 semitones
A seventh stretched to the width of an octave, produced by chromatic spelling.
Also written A7 · 7A
Augmented Seventh
7A · 12 semitones
On the piano, from every note
| From | Notes | Play it on your instrument |
|---|---|---|
| C | C – B# | |
| C# | C# – B## | |
| D | D – C## | |
| Eb | Eb – D# | |
| E | E – D## | |
| F | F – E# | |
| F# | F# – E## | |
| G | G – F## | |
| Ab | Ab – G# | |
| A | A – G## | |
| Bb | Bb – A# | |
| B | B – A## |
Tap a key or a fret to hear it.
Read on: number and quality · inversion · consonance and dissonance
Every seventh
A seventh can take these qualities, one semitone apart; choose one to see the upper note move and hear the pair.
Understanding Augmented Seventh
Names and symbols
Augmented Seventh is written A7, 7A: the letter is the quality, the number the size. Chord formulas on this site write the number first, as tonal does.
The octave is the one interval every tradition names the same way. An augmented seventh and a diminished ninth sound exactly like it and are written only when the spelling of a chord or a line demands them.
How it sounds
An augmented seventh spans 12 semitones: C – B#. It sounds like an octave, and it is written as a seventh because the upper note is a chromatically raised seventh degree rather than a repeat of the root.
Where it comes from
It appears in dense chromatic writing and in theoretical keys requiring double accidentals. In practice most readers meet it only when analysing why a passage is spelled the way it is.
Learn this properly
Chapter 5: IntervalsCommon questions
- How many semitones is an Augmented Seventh?
- Twelve — C – B# — the same distance as an octave. Count the semitones of any interval with the interval calculator.
- Is an augmented seventh the same as an octave?
- The same sound, different letter names and different function. The upper note is a raised seventh degree, not the root repeated.
- Where would I see one?
- In heavily chromatic music where spelling has to track the harmonic function of each voice.
- How do I play Augmented Seventh?
- On guitar the handiest shape is Next string, B 1 · E 8, read as string and fret; the instrument panel draws it from any starting note with the other shapes. On the piano count 12 semitones up from any key, black keys included. Play the notes together for the harmonic form, one after the other for the melodic form.
- What is the inversion of Augmented Seventh?
- The inversion of Augmented Seventh is the Diminished Second: put the lower note an octave higher and the distance that remains is the inversion. The two always add up to an octave, 12 semitones and no semitones, and swap their qualities between major and minor, or keep perfect as perfect.