A time signature (also known as meter signature,Alexander R. Brinkman, Pascal Programming for Music Research (Chicago: University of Chicago Press, 1990): 443, 450–63, 757, 759, 767. ; Mary Elizabeth Clark and David Carr Glover, Piano Theory: Primer Level (Miami: Belwin Mills, 1967): 12; Steven M. Demorest, Building Choral Excellence: Teaching Sight-Singing in the Choral Rehearsal (Oxford and New York: Oxford University Press, 2003): 66. ; William Duckworth, A Creative Approach to Music Fundamentals, eleventh edition (Boston, MA: Schirmer Cengage Learning, 2013): 54, 59, 379. ; Edwin Gordon, Tonal and Rhythm Patterns: An Objective Analysis: A Taxonomy of Tonal Patterns and Rhythm Patterns and Seminal Experimental Evidence of Their Difficulty and Growth Rate (Albany: SUNY Press, 1976): 36–37, 54–55, 57. ; Demar Irvine, Reinhard G. Pauly, Mark A. Radice, Irvine’s Writing about Music, third edition (Portland, Oregon: Amadeus Press, 1999): 209–210. . metre signature,Henry Cowell and David Nicholls, New Musical Resources, third edition (Cambridge and New York: Cambridge University Press, 1996): 63. (cloth); (pbk); Cynthia M. Gessele, "Thiéme, Frédéric [Thieme, Friedrich]", The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell (London: Macmillan Publishers, 2001); James L. Zychowicz, Mahler's Fourth Symphony (Oxford and New York: Oxford University Press, 2005): 82–83, 107. . and measure signature)Edwin Gordon, Rhythm: Contrasting the Implications of Audiation and Notation (Chicago: GIA Publications, 2000): 111. . is an indication in music notation that specifies how many note values of a particular type fit into each measure (bar). The time signature indicates the meter of a musical movement at the bar level.
In a music score the time signature appears as two stacked numerals, such as (spoken as four–four time), or a time symbol, such as or (spoken as common time or cut time, respectively). It immediately follows the key signature (or if there is no key signature, the clef symbol). A mid-score time signature, usually immediately following a barline, indicates a change of meter.
Most time signatures are either simple (the note values are grouped in pairs, like , , and ), or compound (grouped in threes, like , , and ). Less common signatures indicate complex, mixed, additive, and irrational meters.
Time signature notation Most time signatures consist of two numerals, one stacked above the other:
The lower numeral indicates the note value that the signature is counting. This number is always a power of 2 (unless the time signature is irrational), usually 2, 4 or 8, but less often 16 is also used, usually in Baroque music. 2 corresponds to the half note (minim), 4 to the quarter note (crotchet), 8 to the eighth note (quaver), 16 to the sixteenth note (semiquaver). The upper numeral indicates how many such note values constitute a bar. For instance, means two quarter-notes (crotchets) per bar, while means four eighth-notes (quavers) per bar. The most common time signatures are , , and .
Symbolic signatures
By convention, two special symbols are sometimes used for and : The symbol is sometimes used for time, also called common time or imperfect time. The symbol is sometimes used in place of and is called alla breve or, colloquially, cut time or cut common time. These symbols derive from mensural time signatures, described below.
Frequently used time signatures
Simple versus compound Simple meters are those whose upper number is 2, 3, or 4, sometimes described as duple meter, triple meter, and quadruple meter respectively.
In compound meter, the note values specified by the bottom number are grouped into threes, and the upper number is a multiple of 3, such as 6, 9, or 12. The lower number is most commonly an 8 (an eighth-note or quaver): as in or .
Other upper numbers correspond to irregular meters.
Beat and subdivision
Musical passages commonly feature a recurring pulse, or beat, usually in the range of 60–140 beats per minute. Depending on the tempo of the music, this beat may correspond to the note value specified by the time signature, or to a grouping of such note values. Most commonly, in simple time signatures, the beat is the same as the note value of the signature, but in compound signatures, the beat is usually a dotted note value corresponding to three of the signature's note values. Either way, the next lower note value shorter than the beat is called the subdivision.
On occasion a bar may seem like one singular beat. For example, a fast waltz, notated in time, may be described as being one in a bar. Conversely, at slow tempos, the beat might even be a smaller note value than the one enumerated by the time signature.
Mathematically the time signatures of, e.g., and are interchangeable. In a sense all simple triple time signatures, such as , , , etc.—and all compound duple times, such as , and so on, are equivalent. A piece in can be easily rewritten in , simply by halving the length of the notes.
Other time signature rewritings are possible: most commonly a simple time-signature with triplets translates into a compound meter.
The choice of time signature in these cases is largely a matter of tradition. Particular time signatures are traditionally associated with different music styles—it would seem strange to notate a conventional rock song in or , rather than .
Examples In the examples below, bold denotes the primary stress of the measure, and italics denote a secondary stress. Syllables such as "and" are frequently used for pulsing in between numbers.
Simple: is a simple triple meter time signature that represents three quarter notes (crotchets), usually perceived as three beats. In this case the subdivision would be the eighth note (quaver). It is felt as
Compound: Most often, is felt as two beats, each being a dotted quarter note (crotchet), and each containing subdivisions of three eighth notes (quavers). It is felt as
The table below shows the characteristics of the most frequently used time signatures. Simple time signatures Time signature Common uses Simple drum patternVideo representation or (quadruple) Common time: Widely used in classical music and most forms of popular music. Most common time signature in rock, blues, country, funk, and pop.Scott Schroedl, Play Drums Today! A Complete Guide to the Basics: Level One (Milwaukee: Hal Leonard Corporation, 2001), p. 42. . or (duple) Alla breve, cut time: Used for marches and fast orchestral music.(duple) Used for polkas, galops, marches, and many styles of Latin music (including bolero, cumbia, and merengue). (triple) Used for waltzes, minuets, scherzi, polonaises, mazurkas, country & western ballads, R&B, and some pop. (triple) Also used for the above but usually suggests higher tempo or shorter hypermeter. Sometimes preferred for certain folk dances such as cachucha. Compound time signatures Time signature Common uses Simple drum pattern Video representation (duple) Double jigs, jotas, zortzikos, polkas, sega, salegy, tarantella, marches, barcarolles, loures, and some rock music. Anapestic tetrameter poetry also fits into time when said aloud. (triple) Compound triple time: Used in slip jigs; otherwise occurring rarely ("The Ride of the Valkyries", Tchaikovsky's Fourth Symphony, and the final movement of J.S. Bach's Violin Concerto in A minor (BWV 1041) are familiar examples. Debussy's "Clair de lune" and the opening bars of Prélude à l'après-midi d'un faune are also in , as well as the title screen theme from The Legend of Zelda: The Wind Waker.) (quadruple) Also common in slower blues (where it is called a shuffle) and doo-wop; also used more recently in rock music. Can also be heard in some jigs like "The Irish Washerwoman". This is also the time signature of Scene by the Brook, the second movement of Beethoven's Pastoral Symphony.
Tempo giusto
While changing the bottom number and keeping the top number fixed only formally changes notation, without changing meaning – , , , and are all three beats to a meter, just noted with eighth notes, quarter notes, half notes, or whole notes – these conventionally imply different performance and different tempi. Conventionally, larger numbers in the bottom correspond to faster tempi and smaller numbers correspond to slower tempi. This convention is known as tempo giusto, and means that the tempo of each note remains in a narrower, "normal" range. For illustration, a quarter note might correspond to 60–120 bpm (quintuplet 75–150, triplet 90–180 and septuplet 105–210), a half note to 30–60 bpm (triplet 45–90), a whole note to 15–30 bpm, and an eighth note to 120–240 bpm; these are not strict, but show an example of "normal" ranges.
This convention dates to the Baroque era, when tempo changes were indicated by changing time signature during the piece, rather than by using a single time signature and changing tempo marking.
Complex time signatures
Signatures that do not fit the usual simple or compound categories are called complex, asymmetric, irregular, unusual, or odd—though these are broad terms, and usually a more specific description is any meter which combines both simple and compound beats.
Irregular meters are common in some non-Western music, and in ancient Greek music such as the Delphic Hymns to Apollo, but the corresponding time signatures rarely appeared in formal written Western music until the 19th century. Early anomalous examples appeared in Spain between 1516 and 1520,Tim Emmons, Odd Meter Bass: Playing Odd Time Signatures Made Easy (Van Nuys: Alfred Publishing, 2008): 4. . "What is an 'odd meter'?...A complete definition would begin with the idea of music organized in repeating rhythmic groups of three, five, seven, nine, eleven, thirteen, fifteen, etc." plus a small section in Handel's opera Orlando (1733).
The third movement of Frédéric Chopin's Piano Sonata No. 1 (1828) is an early, but by no means the earliest, example of time in solo piano music. Anton Reicha's Fugue No. 20 from his Thirty-six Fugues, published in 1803, is also for piano and is in . The waltz-like second movement of Tchaikovsky's Pathétique Symphony (shown below), often described as a "limping waltz", is a notable example of time in orchestral music.
Examples from 20th-century classical music include: Gustav Holst's "Mars, the Bringer of War" and "Neptune, the Mystic" from The Planets (both in ) Paul Hindemith's "Fuga secunda" in G from Ludus Tonalis () the ending of Stravinsky's The Firebird () the fugue from Heitor Villa-Lobos's Bachianas Brasileiras No. 9 () the themes for the Mission: Impossible television series by Lalo Schifrin (in ) and for Room 222 by Jerry Goldsmith (in ) In the Western popular music tradition, unusual time signatures occur as well, with progressive rock in particular making frequent use of them. The use of shifting meters in The Beatles' "Strawberry Fields Forever" and the use of quintuple meter in their "Within You, Without You" are well-known examples,Edward Macan, Rocking the Classics: English Progressive Rock and the Counterculture (New York: Oxford University Press, 1997): 48. . as is Radiohead's "Paranoid Android" (includes ).Radiohead (musical group). OK Computer, vocal score with guitar accompaniment and tablature (Essex, England: IMP International Music Publications; Miami, Florida: Warner Bros. Publications; Van Nuys, California: Alfred Music, 1997): . .
Paul Desmond's jazz composition "Take Five", in time, was one of a number of irregular-meter compositions that The Dave Brubeck Quartet played. They played other compositions in ("Eleven Four"), ("Unsquare Dance"), and ("Blue Rondo à la Turk"), expressed as . "Blue Rondo à la Turk" is an example of a signature that, despite appearing merely compound triple, is actually more complex. Brubeck's title refers to the characteristic aksak meter of the Turkish karşılama dance.