Minor 7th Chords are represented as m7 or -7, with m7 being the most popular... the 7th note is a minor 7th above the root note or tonic.
The chord is in essence a Minor Minor 7th chord - a minor chord with an added minor 7th. This in in contrast to a Minor Major 7th chord - a minor chord with an added major 7th.
Minor 7th chord: root - minor 3rd - perfect 5th - minor 7th
Chord formula:1 - ♭3 - 5 - ♭7
We calculate the notes of a chord from the Major Scale of that particular chord, e.g., the notes of a Gm7 chord are derived from the G Major Scale, the notes of a Cm7 chord are derived from the C Major Scale etc. In the following example, we will calculate the notes of a Bm7 chord:
Chord Name + (other less-common names)
Bm7 ( B min7, B-7)
B Major Scale (B chords are derived from the B Major Scale)
B - C# - D# - E - F# - G# - A# - B
Chord Formula for all m7 chords
1 - ♭3 - 5 - ♭7
Chord Notes (after applying the formula to the Scale)
B - D - F# - A
Chord notes on the Treble Clef
Here are some more examples for calculating the notes of a minor 7 chord: