The direction of the note stem
Five cases to hear and see: the same bar once set properly, once with the stem forced the other way. The sound stays the same.
The note stem says nothing about the sound. It points up or down so that the note stays inside the staff instead of running off the edge. The rule is the middle line — the third of the five: below it the stem points up and sits on the right of the head, on it and above it the stem points down and sits on the left.
In the treble clef the middle line is B4, in the bass clef D3. So it is not a fixed pitch but a position on the staff — the same B4 gets a different stem in a different clef.
On this page every case stands twice side by side: on the left as it ought to be set, on the right with the opposite forced. Both sound alike — pitches and onsets were measured from the sound, the stem direction from the engraved image.
Below the middle line
An E4 sits below the middle line, so the stem points up and sits on the right of the head. That keeps it inside the staff. On the right the same E4 with the stem forced down: it pushes out below the staff, and reading gets harder. The pitch is the same in both images.
On and above the middle line
A C5 lies above the middle line, so the stem points down and sits on the left of the head. The boundary is sharp: B4 on the middle line already takes a downward stem. On the right the same note with the stem forced up — the same pitch again, a different picture.
Chord: the furthest note decides
A chord has three heads and one stem. Its direction is decided by the note furthest from the middle line. Here the lowest note lies further away than the highest, so the stem points up — even though one of the notes sits above the middle line. On the right the same chord forced downward.
Beamed group: one direction for all
Four eighths under a beam. On their own they would point different ways, since two lie below and two above the middle line. A beam ties them into one group, and the group takes a single direction — by the same measure: the note furthest away decides. On the right the same group forced upward.
Two voices: pointing away from each other
Two voices on one staff. Here it is no longer the position that counts but the voice: the upper takes the stem up, the lower takes it down, even where both would sit on the same side of the middle line. That way a reader sees at once which note belongs to which voice. On the right the same thing swapped — and that is exactly when you lose the thread.
The middle line decides
Three cases go beyond the simple rule, and those are the ones that trip readers up. In a chord the deciding note is the one furthest from the middle line — not the highest and not the lowest. A beamed group takes one single direction for all its notes, even where individual notes would stand the other way. And where two voices share a staff, the upper always points up and the lower always down, wherever the notes happen to lie: there the stem tells you which voice a note belongs to.
A whole note has no stem at all. The question only arises from the half note on — and from the eighth on the flag joins it, always on the same side as the stem.
What stands next to it
How long a note lasts and where the stem comes from in the first place: Note values. How to read a piece of music from the start: How to read sheet music.
Music symbols · How to read sheet music · Music notation glossary
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See AnotonaEvery note on this page is computed, not typed in — following the rule that also makes F# major spell its seventh degree E#, not F.