I'm new studying music, and I have a question about the value of a bar, I'm not sure but seems that I can put any number of notes, considering the prestablished meter, and practically make it of any length. I would like to know if is any kind of rule about the length of a phrase. Thanks.

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5 Answers 5


The time signature indicates the total lengths of all the notes in a bar. So if the time signature is 4/4, then you could have:

  • One semibreve/full note
  • Two minims/half notes
  • Four crotchets/quarter notes
  • Eight quavers/eighth notes
  • ...and so on

Or you could have any mixture of different length notes that adds up to the same total.

  • And with non equivalent values?
    – J.Doe
    May 6, 2017 at 22:45
  • 1
    Each bar of your image adds up correctly to three quarter notes, corresponding to the 3/4 time signature. The brackets over the notes marked with "3" are triplets, and mean that the three notes are played in the time of two ordinary notes. If you hadn't learned that yet, then you would be confused about having "too many notes in a bar."
    – user19146
    May 7, 2017 at 0:42
  • 1
    "is any kind of rule about the length of a phrase" - No, a phrase can be any length, but especially in popular music phrases are often 4 bars long. Your image seems to be just one 11-bar phrase, though.
    – user19146
    May 7, 2017 at 0:43

If the music has a time signature (and the majority of western music that is performed today does have one) then the "number of notes" in each bar should match the time signature, as in Simon B's example.

There are a small number of exceptions to that "rule" - for example, a piece of music can start "in the middle of a bar", and the first bar of the score (often called a "pickup bar") will have fewer notes than the time signature indicates, because the rests and the start of the bar are not written. The same can apply to the last bar of the score, and repeated sections (shown by signs which look similar to bar lines) can also start and end in the middle of bars.

Before about 1700, a lot of music (except for dance music, which by its nature usually has a regular rhythm) did not have a time signature, and the bar lines were mainly to indicate the start of the musical phrases, and provide a reference points if the piece was for several performers.

Some contemporary music also does not use time signatures, but if you are just beginning to study music with an teacher, most likely all the music that you study in the first stages of the course will have time signatures.

  • Ok, but I think have read some sheets that have non symmetrical values, like 4-4 meter and 12 notes grouped in 3-8. 12-8 isn't a 4-4 equivalent, maybe 8/4, but 12/4 doesn't fit. Maybe it's syncopation.
    – J.Doe
    May 6, 2017 at 22:41

You are correct. Any number of notes may be placed within a measure, so long as the sum of those notes equals that of the pre-established meter.

Phrases, on the other hand, may be any length. With that being said, classical music tends to be divided by phrases consisting of four or eight measures each. Phrases in popular music also tend to be four bars in length. While this is more a matter of customary tradition, there is not a necessary rule for the length of phrases, unlike for that of measures.

  • Phrases are usually based on the harmonic progression. Jun 22, 2017 at 17:56
  • It should perhaps be pointed out that the musical example here is from Giovanni da Firenze, mid- 14th century, and the phrase length is based on the cantus firmus length, not harmony. Phrase lengths based on harmonic progressions don't show up until much later. Aug 22, 2017 at 10:42

but I think have read some sheets that have non symmetrical values, like 4-4 meter and 12 notes grouped in 3-8. 12-8 isn't a 4-4 equivalent, maybe 8/4, but 12/4 doesn't fit. Maybe it's syncopation.

answer to your comment above:

12-8 is an 4-4 equivalent, it's quite identical!

you can consider the 3/8 as a triplets. (same for 12-4: this will fit to 4-2 where 3 quarters will be notated as triplets.


12-8 is compound, split into 4 dotted crotchet beats, or 4 x 3 quavers, whereas 4-4 is 4 normal crotchets and splits into two quavers. It's just the difference between wanting a simple time signature, where the beats all split into two, or a compound, where the beat (most often) splits into 3. If you have 12-8, you can have 4 lots of 3 quavers in a bar, 12, whereas 4-4 splits into 8 quavers, 4 lots of 2 quavers (if grouped according to the beat!).

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