Identify
Work backwards: from a shape under your fingers to its name, or from a handful of chords to the key they belong to.
What chord is this?
Enter the shape you're fretting to see what chord it names, including inversions and slash chords.
Most likely
Em7add11
also G6add9/E, A11/E, A9sus4/E
E2 A2 D3 G3 B3 E4
What key am I in?
List the chords in a progression to see which keys they fit, ranked best match first.