Music theory · 6 min read

Time signatures explained

The two numbers after the clef tell you how many beats are in a bar and which note gets the beat. Here is how to read simple, compound and odd metres.

2026-06-14

Reading the two numbers

After the clef and the key signature sits a pair of numbers, one above the other. They are not a fraction, despite appearances, and nobody should ever read them aloud as three over four. They are two separate pieces of information.

The bottom number names a note value by a simple code: 1 is a whole note, 2 a half note, 4 a quarter note, 8 an eighth note, 16 a sixteenth. The top number counts how many of those fit in one bar. So 3 over 4 means three quarter notes per bar. 6 over 8 means six eighth notes per bar. 2 over 2 means two half notes.

A bar, or measure, is the space between two vertical barlines. Its purpose is purely to organise the pulse into repeating groups so that your eye and your counting stay synchronised with the music. The first beat of each bar carries a natural emphasis, which is most of what gives a metre its character.

Simple time: the beat divides in two

In simple time, each beat splits naturally into two halves. The common signatures are 2 over 4, 3 over 4 and 4 over 4, counted one-two, one-two-three, and one-two-three-four respectively.

4 over 4 is so widespread it is often printed as a letter C, standing for common time rather than for the word common as most students assume; it descends from a medieval broken-circle notation. A C with a vertical line through it is cut time, or 2 over 2, where you feel two slow beats per bar instead of four quick ones. The notes on the page can look identical; what changes is how you count and, crucially, how you phrase.

3 over 4 gives you waltz, minuet and a great deal of folk music. 2 over 4 gives marches, polkas and the tango's habitual pulse. These are not neutral containers. A bar of three has a lilt built into it that a bar of four does not.

Compound time: the beat divides in three

6 over 8 confuses people because the top number suggests six beats, and in practice you almost never count six. You count two, each of which contains three eighth notes. That is compound time: the beat divides into three rather than two.

The others in the family are 9 over 8, felt as three beats of three, and 12 over 8, felt as four beats of three. A 12 over 8 shuffle is the entire rhythmic foundation of slow blues. The lilting quality people describe in a 6 over 8 jig comes directly from that triple subdivision.

The test that settles it: count the piece at speed. If you are counting six in a fast 6 over 8, you are counting the subdivision, not the beat. At any real tempo, 6 over 8 has two pulses and 3 over 4 has three, and though both bars contain six eighth notes, they group them differently and sound nothing alike. Composers from Bernstein to Piazzolla have made whole careers out of switching between the two.

Odd and shifting metres

Some music groups its beats unevenly. 5 over 4 is counted either as three plus two or two plus three, and the choice changes everything: the theme from Mission: Impossible and Dave Brubeck's Take Five are both in five but feel quite different. 7 over 8 is usually three plus two plus two, or some other arrangement the composer will make audible through accents.

Balkan folk music lives in these metres as naturally as Viennese music lives in three, and accordionists who play Bulgarian or Macedonian repertoire stop finding 7 over 8 exotic fairly quickly. The trick is to stop counting individual eighth notes and start feeling the uneven groups as long and short beats: long-short-short rather than one-two-three-four-five-six-seven.

Metres also change mid-piece. Stravinsky famously changes almost every bar. When a new time signature appears, it takes effect from that bar until it is replaced.

Metre at the instrument

For the accordionist, metre is a bellows question before it is a counting question. The bellows are how you produce dynamics and how you articulate, and a change of direction is an event the listener hears whether you intend it or not. Plan direction changes so they fall at the start of a bar or the start of a phrase, never in the middle of a sustained note that ought to sound continuous. In a waltz, a small increase in bellows pressure on beat one and a lightening on beats two and three will do more for the dance feel than any amount of accurate counting.

For the double bassist, metre is felt through the right arm. In 4 over 4 jazz walking, the bow or the plucking finger marks four equal beats with the emphasis placed by length rather than volume. In cut time you draw longer, and in 6 over 8 you shape the triplet so the first of each group of three carries the weight.

Practise with a metronome set to the beat rather than the subdivision, then set it to click on beat one only and see whether you can hold a bar of three or five without drifting. It is humbling. Every ensemble class at A&G Academy starts with some version of it, because a room that agrees on where beat one is can survive almost anything else going wrong.

Frequently asked

What is the difference between 6/8 and 3/4?

Both bars hold six eighth notes, but they group them differently. 3 over 4 is three beats each splitting into two, counted one-and two-and three-and. 6 over 8 is two beats each splitting into three, counted one-two-three four-five-six with weight on one and four. Same quantity, different pulse, entirely different feel.

What does the C at the start of some music mean?

It is common time, equivalent to 4 over 4, and it comes from a medieval broken circle rather than from the word common. A C with a vertical stroke through it means cut time, or 2 over 2, where you feel two slow beats per bar instead of four. Cut time usually implies a brisker, broader phrasing.

How do I count odd time signatures like 7/8?

Stop counting every eighth note and feel the groups instead. 7 over 8 is usually three plus two plus two, so count long-short-short and let your body keep the pattern. Playing along with recordings of Balkan folk music or progressive rock is far more effective than counting on paper.


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