semicord

A A major chord

Notes
A C# E
Formula
1 3 5
Semitones
0 4 7 above the root
Other symbols
AM, Amaj

A to C# is a major third (4 semitones), C# to E is a minor third (3 semitones). The major triad: a major third with a minor third on top, the tonic chord of the key of A major.

A on the piano

C4D4E4F4G4A4B4C5D5E5F5G5A5B5C#4Eb4F#4Ab4Bb4C#5Eb5F#5Ab5Bb5C4AC5C#E

Root position from A4: A4, C#5, E5. Middle C is C4.

A on the guitar

Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has A as its lowest note.

×AEEAAC#C#E
Open position (A-shape)
x 0 2 2 2 0 (low E to high e)
Sounds A2 E3 A3 C#4 E4
5frAAEEAAC#C#EEAA
E-shape barre, root on the E string at fret 5
5 7 7 6 5 5 (low E to high e)
Sounds A2 E3 A3 C#4 E4 A4

The barre shapes are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play major chords on other roots.

Inversions of A

An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.

PositionNotes, bass firstNamedListen
Root positionA C# EA
1st inversionC# E AA/C#
2nd inversionE A C#A/E

Where A fits

A is I in A major, IV in E major, V in D major, V in D minor. As V in a minor key it comes from the harmonic minor scale, whose raised seventh degree is this chord's third, C#.