Also does it vary on the time signature? I see that some have two bars some have four as well, Also when there is a new staff created underneath a previous one, is there a name for it like placing another treble clef staff underneath a previous one continuing the melody? See how the sheet music below has 4 bars and 2, why does it have to be 4 and the other one being 2? Cant it be 5,3,7 etc. is it based off the time sig?

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    When you say '4 bars and 2', do you really mean 5 and 3? Because there are 5 bars on the first line, and 3 on the second.
    – endorph
    Nov 23, 2016 at 21:42
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    I think you are confusing the bar line with the bar/measure, which, now that I think about it, is a little confusing. The bar line is the name of the line separating each measure and a bar is another name for a measure. So the top system has five bars and four bar lines and the bottom has three bars and two bar lines. However, if you count the end of the system as a barline they are equal.
    – user33368
    Nov 23, 2016 at 22:45

4 Answers 4


The correct term for a group of staves that are played simultaneously is a system, but it's often called a "line," which can lead to confusion with other musical meanings of "line."

In general, you can have any number of measures per system, ("measures per staff" in your question isn't really correct) depending on how many notes they contain. This is exactly the same as asking "how many words make a line of text" - it depends if the words are "the cat sat on the mat" or "antidisestablishmentarian countermeasures".

In some situations, for example the music parts for theater performances, there is a convention of always writing exactly four measures per system. This makes it easier to do last-minute edits to the music, especially if most of the songs have four-measure phrases. If can re-print a just small section of the score and insert it into the original version without affecting everything else, you don't lose all the extra markings that the players have made in pencil during rehearsals!

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    There is a little extra confusion because American and British English are different. The vertical lines are always "barlines", but the space between two barlines is called a "bar" in England, and a "measure" in America. I think almost exclusively: I have never heard anyone in England say "measure", but the American Gardner Read's (otherwise excellent) book on music notation has a little rant on the evils of calling a "measure" a "bar"... Nov 24, 2016 at 5:48

If I read your question correctly, I think you're asking about the number of bars on each line, and why it varies.

As far as I know, it's purely practical. Some bars have more notes, so they take up more physical space. Your example is also skewed by the fact that the piece ends. If there was another bar, I suspect it would end up on the same line.

Sometimes it gets split up so that the end of the musical phrase is also the end of the line, but there's no musical reason to do that. It can make it somewhat easier to read.


As many as are needed. As many as facilitate readable note and lyrics (if any) spacing. As many as facilitate a neat page layout, without a short last line. Often 4.


I am just about to graduate with my production degreee, which requires quite a lot of lead sheet writing and sheet music digestion, and I had this question pop up the other day on a quiz. What my prof. said (which it still could be a matter of his option when it comes to composition) that you should separate 4-8 bars if possible. Obviously there are instances where you can not avoid that, but as far as writing a composition, group in 4's. (Via Full Sail University)

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    Please could you give a citation for this view? If you look at actual sheet music by reputable publishers, you'll see systems with 3, 4, 5, 6, 7, all sorts of numbers of bars per system, depending on how much room each bar needed. Yes, there are conventions on laying the music out so that certain moments fall at the end of a line, e.g. the end of each song or movement, or the end of each variation in a Theme and Variations. But not every 4 bars.
    – Rosie F
    Jun 25, 2020 at 6:08

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