How are measures measured in music?

Yet, there are so many numbers and so many ways for these numbers to be written:

These are just some of the time signatures you might encounter. Notice also in the above image that there are time signatures in the form of letters instead of numbers, which adds even more possibilities and potential complications into the mix; however, these letters really just stand in for numbers with added special meanings.

All of these time signatures raise the questions: do we really need all of these different time signatures? Do they really mean different things? Why do composers and musicians prefer some time signatures over others? These time signatures really do have slightly different meanings and purposes in music, but some can sound the same to the ear. Some are quite rare and others are more common.

This article will explain the basics of reading time signatures and meters, show how the various time signatures are related to each other and can sound similar and different, and why composers might choose certain time signatures over others.

Sound in Time

Fundamental to the definition of music itself is that music must move through time—it is not static. Hence, music is sound organized through time. This organization of music through time is managed in the Western music system through time signatures.

The time signatures give us a way to notate our music so that we can play the music from scores, hear its organizational patterns, and discuss it with a common terminology known to other musicians. The organizational patterns of beats, as indicated by the time signature, is how we hear and/or feel the meter of said piece. When discussing music, the terms "time signature" and "meter" are frequently used interchangeably; but time signature refers specifically to the number and types of notes in each measure of music, while meter refers to how those notes are grouped together in the music in a repeated pattern to create a cohesive sounding composition. The methods for classifying the various time signatures into meters is discussed in detail later in this article.

Meters vs. Rhythms

Meter is the comprehensive tool we used to discuss how music moves through time. That said, there is another way that musicians also discuss how music moves through time, and that is through rhythm. Rhythms are the lengths of the notes in the music itself - which notes are long and which notes are short. Musicians learn how to play these rhythms in the context of each piece  by using the time signature.

The Notation

In musical scores, we organize the music into “bars” or measures. A “barline," or measure line, is where the five horizontal lines of a staff are intersected vertically with another line, indicating a separation:

Each measure has a specific number of notes allowed to be placed in it, and that number of notes is dependent upon the time signature.

Notes

The most common notes which are used to make the short and long rhythms in the various meters are included in the chart below, beginning with the longest held notes and going to the shortest. This chart also mentions the length relationship between the note values.

As the notes in the various metric breakdowns get bigger or smaller, the equivalent relationships continue. For example, a double-whole note would last as long as eight quarter notes!

Reading the Time Signatures

The number of notes allowed in each measure is determined by the time signature. As you saw in the time signature examples above, each time signature has two numbers: a top number and a bottom number: 2/4 time, 3/4 time, 4/4 time, 3/8 time, 9/8 time, 4/2 time, 3/1 time, and so on.

The bottom number of the time signature indicates a certain kind of note used to count the beat, and the top note reveals how many beats are in each measure. If you look at the American note names from the chart above, there is a fun little trick to it:

Take the 2/4 time signature for example - with the 2 on the top of the time signature you know there are 2 beats for one measure, and this leaves you with a fraction of 1/4—a quarter, the note-length the time signature is indicating to you then is a quarter note. Therefore, you know that there are two quarter notes worth of time in every measure:

Let’s try another one. In 9/8 time, you know that in every measure there are 9 notes in a 1/8 length.

How about in 4/2 time?

In 4/2 time, each measure has 4 notes of 1/2, so we have 4 1/2  notes:

Now try 3/1 time.

In 3/1 time, so we have 3 notes of a 1/1 length, so 3 whole notes!

Common Time and Cut Time

The above steps are how you figure out the notes and beats of most time signatures, but what about the two time signatures that are letters? As a matter of fact, the two letter time signatures are actually shorthand and variations for the most common numerical time signatures, 4/4 and 2/2.

The 4/4 time signature is so common that it actually has two names and two forms, the first being 4/4, and the second being the 

, literally called “Common Time.” So whenever you see the 

 

Another prevalent time signature is the

. It looks a lot like the “Common Time” signature, except it has a slash through it. Technically, these measures have four quarter notes in them as well, but this one is called “Cut Time,” hence the C being slashed or “cut.” This “Cut Time” change to “Common Time” means it goes twice as fast, so instead of the quarter note getting the beat, the half note gets the beat! The

 

Below is an example from the opening of Edvard Grieg’s Peer Gynt Suite, “In the Hall of the Mountain King.” This excerpt is in marked in Common Time with a big C, which means 4/4. If you count the notes in the measures, you will see that there are four quarter-notes worth of time per measure.

This example is particularly relevant to our discussion of Common and Cut time, because as this piece continues, it gradually increases in speed, moving from sounding like a 4/4 to 2/2. And this is actually what happens! By the end of the piece, the conductor directs the orchestra in Cut Time rather than Common Time. Listen to this performance  to hear the beats get faster and see if you can hear when the orchestra switches into Cut Time!

Meter Classifications

We've talking about the basics of reading and deciphering time signatures - now we get to learn how those time signatures can be understood as meters.

There are two levels of classifying meters. The first level of classification focuses on how the beat indicated by the time signature is subdivided.

There are only two ways for the beat to be regularly subdivided in Western music, and that is into two or into three smaller notes. Refer to the note value charts above. All other subdivisions are either multiples of these two subdivisions, or some complex form of adding them together. For ease of notation and classifying the subdivisions as meters then, we have: Simple Time, Compound Time, and Irregular Time.

Simple Time

Simple time is any meter whose basic note division is in groups of two. Examples of these meters include: Common Time, Cut Time, 4/4, 3/4, 2/4, 2/2, 2/1, and so on. These meters are simple time because the quarter note divides equally into two eighth notes, the half-note divides equally into two quarter notes, or the whole note divides equally into two half notes. You can see these divisions if you refer back to the above note length chart.

Compound Time

Slightly more complicated is compound time, which is any meter whose basic note division is into groups of three. You automatically know you are not in simple time if there is an 8 as the bottom number of your time signature. An 8 to mark simple time would be pointless, as will be demonstrated below in the beat hierarchies and accents section.

So, when you see an 8 as the bottom number of your time signature, you know that your eighth notes should be grouped together in groups of three instead of two! In 6/8, you have two groups of three eighth-notes, in 9/8 you have three groups of three eighth notes, and 12/8 has four groups of three eighth notes.

Technically, to get a compound time sound, composers could use a simple time signature and then mark all of the main beat subdivisions in triplets - making a duple division into a triple division - throughout an entire piece to get the same effect. However, using triplets throughout an entire piece to get a compound time sound would appear quite messy and cluttered on the page.

An example of the 12/8 against the 4/4 using triplets is in the table below. To the listener, these examples sound exactly the same, and in practice there is the added risk of confusing performers unused to switching between time signatures.

Even though it's more common to see a simple time signature with the duple divisions in Western music for music of the past five or six centuries, it was actually compound time which developed and was notated first! Because Western music notation developed alongside church music, much of the underlying theory surrounding music had a theological basis. For meter, the most common subdivision was in compound or triple divisions to relate musical time being three in one, similar to the Christian Trinity of the Father, the Son, and the Holy Ghost.

Irregular Time

The final option for beat subdivision is an irregular or unequal subdivision of the beat.

Even though these are “irregular” meters, they do have patterns that are discernable for the performer. The most common irregular meters actually mix simple time and compound time together within a single measure. Thus, in each measure, there are beats with three subdivisions and there are beats with two subdivisions. Examples include such time signatures as 5/8 and 7/8. Because there are 5 eighth notes per measure or 7 eighth notes per measure, you cannot have equal groupings of 2 or 3 eighth notes. Therefore, similarly to 6/8, 9/8, and 12/8, in which the groups of eighth-notes are beamed together to a larger count, in 5/8 and 7/8 they are also beamed together to make a larger count. However, because the number of eighth notes in 5/8 and 7/8 is odd (and prime), the count lengths in each measure are uneven—or irregular. The eighth note typically stays the same length, but because some counts have two and some counts have three eighth notes, they are irregular!

You can see the groupings of three eighth notes with two eighth notes in each measure of 5/8 above, and groups of two eighth notes against two groups of two eighth notes in each measure of 7/8. In 5/8 and 7/8 then, the first count of each measure is one eighth-note longer than the rest of the counts. Depending on where the placement of the longer beat, composers can create different accents and atmospheres.

Russian composer Pyotr Tchaikovsky (1840—1893) uses an irregular meter in the second movement of his Sixth Symphony. When you listen to the movement, it sounds like it should be a waltz with three beats per measure, but the “beats” of the meter are uneven, sometimes the first beat is longer, sometimes it is shorter because the subdivisions are irregular. To the listener, because it sounds like a waltz and like a dance, it feels at once familiar, but then also lopsided and distant. The irregular beat patterns are unexpected and un-danceable (at least without some serious practice and memorization!). The familiar becomes distorted, distant, potentially dangerous and frightening.

Duple, Triple, and Quadruple Classifications

The second level of classification for meters is how many beats there are in a measure. There are three which are the most common: duple (2/2, 2/4, 6/8), triple (3/4, 9/8, 3/2), and quadruple (4/4, 12/8, 4/2). A duple meter has two beats per measure, a triple meter has three beats per measure, and a quadruple meter has four beats per measure. It is rare to see any larger or smaller that are not an equivalent to one of these three.

Cut-Time is duple and simple meter because there are two beats per measure and those beats are divisible by two:

3/4 time is triple and simple meter because there are three beats per measure and each beat is divisible by two:

4/2 is quadruple and simple meter because there are four beats per measure and each beat is divisible by two:

6/8 time is duple and compound meter because there are two beats per measure and each beat is divided into three:

9/8 time is triple and compound meter because there are three beats per measure and each beat is divided into three:

5/8 time is duple and irregular meter because there are two beats per measure and each beat is divided irregularly:

Look through your scores at home: what are some of the meter classifications that you have been playing?

As you can see from the above explanations of the various time signatures and their meters, there are a lot of similarities and subtle nuances between all of these meters. For example, all of the duple and quadruple time meters are similar in that they have two and four beats per measure. This trait makes them sound very similar to the ear.

Depending on the tempo of the piece, triple and simple time pieces can sound compound and some compound pieces (i.e. 6/8) can sound like they have a simple beat subdivision but triple (i.e. the 6/8 sounding like 3/4)! What helps to distinguish a lot of these meters is the beat hierarchies and typical styles of music in which they are employed.

Beat Hierarchies

Music is sound organized through time, and the time signature tells us how to structure that music in time.

Another important piece of information within that time signature is which notes—which beats—are more important and should get accented. This accentuation of beats is known as a “beat hierarchy.” In almost all Western Classical music, the first beat of every measure is the strongest and most important beat, and should carry the most weight. In duple meters then, the second beat is weak and any subdivisions of the beat are weaker still. In quadruple meters, beat three of the measure is actually stronger than beat two, but not quite as strong as beat one, and beat four should lead into the next downbeat (beat one of the next measure). Triple time starts with a strong beat one, has a weak beat two, and then begins to build on beat three (leading to beat one again).

Understanding the beat hierarchies of the different time signatures can help you to interpret repertoire, especially those that use minimal articulation. For example, check out this 3/2 example from the Spirtuoso movement in Telemann’s Fantasia #6 for solo flute:

Because this piece is marked in 3/2 time, it should be in triple and simple time. However, there are no phrase markings and some musicians who have studied Baroque performance practices have argued for sections of this piece being in two instead of three. Switching the meter from a two to three feel is like giving the piece a 6/8 time signature and making the 6/8 eighth note equal to a 3/2 quarter note. With a 6/8 type meter, the Fantasia would be duple and compound, changing the beat hierarchy and accents from every second quarter note to every third quarter note.

Hemiola

The particular Telemann example above, when performed with a changing beat hierarchy, can be an example of a metric and rhythmic technique called hemiola. Hemiola is a two against three subdivision of beats being played against—and right next—to each other. 

Syncopation

Another way to disrupt the beat hierarchy of meters in music is to use syncopation. Syncopation is the rhythmic shifting of the accented beat from the traditionally strong beats of one and three. In most cases this is done by a really short note on the downbeat which is immediately followed by an accented long note, or having a tie to an un-articulated downbeat, so that the downbeat gets completely lost. A textbook example of how syncopation can disrupt beat hierarchy can be seen in the ragtime piece “The Entertainer” by Scott Joplin.

From the very first verse, the melody line bounces quickly off the sixteenth-note downbeat onto the accented eighth-note. Then, the next measure’s melody downbeat is tied over from the previous measure. Without the score or the repeated eighth-note chords in the left hand of the piano, you would not know where the downbeats were or be able to track the movement of the measures as easily! 

So we have all of these meters and this is how they’re broken down, but… why?

We have all of these different meters and possibilities for subdividing meters to fit the wide variety of music we have! Essentially, different kinds of music require different Simple or Compound time signatures and duple or triple meters. When we connect the music to how it is or was supposed to be used, we find some of the answers to this.

Take a March for example: marches are meant to be, well, marched to, in strict time, and as humans we only have two legs! So out of necessity, marches have to be in a duple or quadruple time. That is why marches are (almost) always in Cut Time, 2/4, 4/4, or on occasion, 6/8. Sousa’s iconic “Stars and Stripes Forever” is in Cut Time. Even though “Stars and Stripes,” and other marches still being composed through today, are rarely still marched to, they are still written in a duple time.

Dance music is another example of music that has to be in a specific meter. Most dances throughout history have had a prescribed number of steps and the music that accompanies the dances must match. For example, waltzes have to be in triple time because they follow a pattern of three steps before repeating the cycle.

The choice of meter and note length provided in the time signature is also a possible indicator of tempo. Generally speaking, one would expect a piece notated in 4/1 to move at a slower tempo than 4/4.

Conclusion

So, that's how you read time signatures! We've investigated how they’re similar and different, how they’re used, and how they can change the music we hear. Many are interchangeable and can sound the same, but have slightly different origins or uses. Meters are how composers organize music through time and communicate that organization to the performers.

For fun, try seeing if you can “play” with any of the meters of your repertoire as if they were in a different meter and tell us about your experiments below!

Learn with LPM

If you are looking to review time signatures, check out our lesson on the Music Theory: How to Read Music course. 

About the Author: Michele Aichele

Michele Aichele is a PhD candidate in Musicology from the University of Iowa, with a MA from the University of Oregon and a BA from Whitman College (Washington). Her interests are in the role of women in composing, performing, teaching, and patronage in music. Her love of learning translates easily to her work with Liberty Park Music. Not only does she get to share her passion for great music and learn from the talented Liberty Park Music teachers, she also gets to help educate more people across the globe through Liberty Park Music’s services.

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