Not every note lasts the same length. Some ring out for an entire bar, while others occupy a fraction of a beat. Note durations describe these lengths. In the basic binary hierarchy, each value is half as long as the one above it.
The duration family
In 4/4 time, a whole note fills an entire bar (4 beats) - the full bar. Halve it and you get two half notes. Split those into quarter notes and keep splitting - the tree continues.
Duration hierarchy in one bar of 4/4
Each duration up close
Whole note
Sustains across all 4 beats. Used for long, held notes - pad chords, sustained strings.
Half note
Two half notes fill one bar. Common in slower melodies and bass parts.
Quarter note
The "standard" beat. When someone says "play on the beat", they usually mean quarter notes.
Eighth note
Counted as "1-and-2-and-3-and-4-and". The "and" is the offbeat eighth note. Hi-hats often play eighths.
Sixteenth note
Counted as "1-e-and-a 2-e-and-a..." Fast hi-hats, detailed drum patterns, and rapid runs use sixteenths.
The halving rule
Each duration is exactly half the length of the previous one. This means you can always substitute one note with two of the next shorter type: one half note equals two quarter notes, one quarter note equals two eighth notes, and so on.
Durations in a DAW
In a piano roll, note duration is the horizontal length of each note block. Your grid snap setting determines the smallest duration you can easily draw. Set grid to 1/16 for detailed work, 1/4 for quick sketching.
Short notes with gaps between them sound staccato and punchy. Longer notes that overlap slightly sound legato and smooth. The grid is visual - you can always adjust notes to any length by dragging their edges.
Try it
Fill one 4/4 bar in three different ways: with one whole note, two half notes, and four quarter notes. Then replace the quarter notes with eight eighth notes and count the added offbeats aloud.
In your DAW, switch the grid between 1/4 and 1/16 and observe which note lengths are easiest to draw at each setting.
Key takeaway
Five main durations: whole (4 beats), half (2), quarter (1), eighth (1/2), sixteenth (1/4). Each is half the length of the previous. In a piano roll, duration = horizontal length. Set your grid snap to control the detail level.
Next: how dotted notes and ties let you create durations that don't fit the standard sizes.
Generate rhythms and grooves
Starts builds drum patterns and rhythmic parts with proper timing, velocity, and groove.