Root, third and seventh: the guide tones fix the quality, so the fifth is dropped. That is what leaves a string free, so pick a tension to put on top.
Fm7 is F, Ab, C and Eb — Fm with the flat seventh added.
It sounds smooth and unhurried. The workhorse of the family, and the chord soul, funk and jazz comp on more than any other.
Pre-dominant — the ii of a major key, and a tonic in its own right.

| F | Ab | C | Eb |
|---|---|---|---|
| 1 | ♭3 | 5 | ♭7 |
Also written Fmin7, F-7 or F minor 7. The same chord either way; which spelling you meet depends on who wrote the chart.
Root, third and seventh. The third and seventh, the guide tones, are what make the chord major, minor or dominant, so the fifth can go: it says nothing the symbol needs.
Three notes means a spare string, which is the real point. Put a tension on it.
Fm7 has 7 of them, on the low-middle three, the bottom three strings, strings 6-4-3 and strings 5-3-2, from open position up to the 13th — all in one inversion, so the bass note never moves. The one to learn first is the F shape at the 6th fret, which is the easiest grip here.
Play Fm7 as a shell — root, third and seventh — and the spare string takes the 9 (G), the 11 (Bb) or the 13 (D).
All 7 common shapes as fret numbers, lowest string first. Hover or tap one to see it drawn.
How you get to it. The turn that lands on Fm7 is Gm7♭5 to C7♭9: the ii and the V of F minor, which is where a minor tonic is usually arrived at rather than simply begun on.
In which keys. Every note of Fm7 belongs to C minor (the iv), C# major (the iii), Eb major (the ii), F minor (the i), Ab major (the vi) and Bb minor (the v).
Every note of Fm7 is in F minor pentatonic, F blues, F dorian, F natural minor and F phrygian.
Change one note of Fm7 and you have Fm (drop the flat seventh), Fm6 (the flat seventh becomes the sixth), Fm7b5 (the fifth becomes the flat fifth), Fm9 (add the ninth), FmMaj7 (the flat seventh becomes the major seventh) or Fmadd9 (the flat seventh becomes the ninth).
Fm7 is a minor chord — root, minor third, fifth. Minor chords on every root.
The common shapes and the derived voicings come from different places, and both are explained in how this site is built.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.