A7 piano chord, A dominant 7th notes and fingering.

The A7 piano chord is A dominant 7th: A, C#, E and G. It is the A major triad (A, C#, E) with a minor seventh (G) added on top, ten semitones above the root. A plain 7 in a chord name, as in A7, always means this flat seventh, not the major seventh.

How to play A7 on piano

1. Find A on the keyboard. A is the white key between the second and third black keys of the group of three.
2. With your right hand, put finger 1 on A, finger 2 on C#, finger 3 on E and finger 5 on G. Finger 1 is the thumb.
3. Press all four keys together. In root position they run from A3 to G4, a reach of 10 semitones. Play chord sounds them together and Arpeggio sounds them one by one, from the bottom up.
4. Click Left hand to see the left hand. It plays A2 to G3, one octave lower: A with finger 5, C# with finger 3, E with finger 2, G with finger 1.
5. The cards under the keyboard hold the four positions, with A, C#, E and G at the bottom in turn. Play and Arpeggio on a card play that position.
6. Open Note names. As written the keys read A, C#, E and G. Sharps shows A, C#, E and G, and Flats shows A, Db, E and G. This chord is written with sharps, so As written and Sharps match.

How A7 is built

Counted from the root, the formula is 0, 4, 7, 10. Stacked on each other the gaps are 4 + 3 + 3: a major third, a minor third and another minor third. The third (C#) and the seventh (G) are 6 semitones apart, which is a tritone, the most tense interval in the chord. That pair is what makes the chord lean toward a resolution.

Worked example: the pitch of A3. On a piano tuned to A4 = 440 Hz, a note 12 semitones below A4 has the frequency 440 × 2^(-12/12), which is about 220.00 Hz. C#4 is 8 semitones below A4, so 440 × 2^(-8/12) gives about 277.18 Hz.

What the keys look like under your hand

A has a black key on each side, Ab on its left and Bb on its right. One of the four notes is a black key (C#) and three are white keys (A, E and G). Finger 2 presses C#, a black key between C and D. The middle fingers are the longest, so they reach black keys most easily.

A7 inversions and fingering

A7 has four positions. In root position A is at the bottom. In the first inversion, C# is at the bottom and the chord is written A7/C#. In the second inversion, E is at the bottom and the chord is written A7/E. In the third inversion, G is at the bottom and the chord is written A7/G. The tightest reach, 8 semitones from the lowest key to the highest, is the first inversion. The widest, at 10, is the root position.

The keys that hold A7

A7 fits two of the major and natural minor keys that have a standard key signature, which means every note of it comes from that key's scale. The simplest is D major, with 2 sharps, where it is chord V7.

Progressions that use A7, with the chord numbers and the chords in that key:

• D major: Imaj7-IVmaj7-V7-Imaj7, which is Dmaj7, Gmaj7, A7, Dmaj7, the three-chord cadence of folk, rock and blues.
• B minor: i7-VII7-VImaj7-VII7, which is Bm7, A7, Gmaj7, A7, a rocking figure between VII and VI.
• D major: vi7-IVmaj7-Imaj7-V7, which is Bm7, Gmaj7, Dmaj7, A7, the four-chord loop started from the vi chord.

Blues: a 12-bar blues in A is built on A7, D7 and E7.

Here is a worked example in D major. The chord before A7 in the first progression above is Gmaj7 (G, B, D and F#). From Gmaj7 in root position, the closest way to reach A7 is its third inversion (G, A, C# and E, lowest note first): one note stays where it is, and the others move 5 semitones in total, counting each note against the note in the same place from the bottom.

Look at the top three notes of A7: C#, E and G make a C# diminished chord (C#, E and G). A dominant 7th is a diminished triad with the root added underneath.

What A7 sounds like

The dominant 7th is restless. Its tritone between C# and G pulls toward a resolution, and the chord most naturally moves to D, a fifth below A. It is the sound of the blues too, where every chord can be a dominant 7th.

Here A7 is the V7 chord in D major and the VII7 chord in B minor. In a 12-bar blues in A the three chords are A7, D7 and E7. In minor keys the same chord appears as V7 of D minor, using the raised seventh of the harmonic minor scale.

A common mistake with A7

A common mistake is pressing G# instead of G on top, one semitone higher than the seventh of A7. That gives Amaj7 (A, C#, E and G#), which sounds soft where A7 sounds restless. Check the top note: it should be the lower of the two keys.

Chords to learn next

Chords close to A7: A major (the same chord without the seventh; shares A, C# and E); Amaj7 (a major seventh instead; shares A, C# and E); Am7 (a minor third instead; shares A, E and G); D major (the chord it leads to; shares A).

Once A7 feels easy, play it and then D major to hear the chord resolve. For chords beyond these six types, and for guitar and ukulele shapes, use the chord finder. To play along with your computer keys, open the virtual piano. The piano chords page lists all 72 chords.