From Zero to Mozart
Stage 2RhythmLesson 16 of 37 · Reading

Simple and compound time

Every time signature answers one question first: does the beat split in two, or in three?

  • Split in two → simple time. 2/4, 3/4, 4/4 — each beat is a quarter note, and a quarter divides into two eighths. Count "1 and 2 and".
  • Split in three → compound time. 6/8, 9/8, 12/8 — each beat is a dotted quarter note, and a dotted quarter divides into three eighths. Count "1‑2‑3, 1‑2‑3" or "1‑&‑a".

That single split — two versus three — changes how a tune feels more than almost anything else.

One beat, split two ways

80 bpm
Simple time. Beat 1 splits into two even eighths — '1 &' — then a plain beat 2. This is the 'straight' feel.
112 bpm
Compound time. Beat 1 fills with three even eighths — count '1 2 3' — then one dotted-quarter note holds all of beat 2 (divisions 4-5-6). This is the 'swung', lilting feel.

Reading the bottom number differently

In simple time the bottom number is the beat: 3/4 means three quarter-note beats. In compound time the bottom number is the division, not the beat: 6/8 doesn't mean six beats — it means six eighth-note divisions, which group into two dotted-quarter beats. Divide the top number by 3 to get the real beat count: 6 ÷ 3 = 2, 9 ÷ 3 = 3, 12 ÷ 3 = 4.

104 bpm
A 6/8 line. Count the six eighth-divisions '1 2 3 4 5 6', leaning on 1 and 4 (the two real beats). Work out which divisions get a note, then reveal.

Sort them

Check yourself

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5

The usual mistake

Counting 6/8 as six beats. It's two, each worth three eighths. Six-beat counting turns a lilting jig into a plod. When you see any x/8, check whether the top number divides by 3 — if it does, it's compound, and the real beat is the dotted note.