In music, tempo refers to the speed or pace of a piece. The word "tempo" comes from Italian, meaning "time," and can be written as "tempos" or "tempi" in plural form. Tempo is measured in beats per minute (bpm) and often shows the feel or mood of a composition. In classical music, tempo is usually written at the beginning of a piece using Italian terms. If a specific speed is needed, it is shown in bpm. In modern classical music, a "metronome mark" (a mark showing only speed) may be used instead of or along with traditional tempo instructions. In modern music like electronic dance music, tempo is often simply stated in bpm.

Tempo, which is the basic beat of music, is one of three elements that create a piece's texture. The other two are meter, shown by a time signature, and articulation, which describes how notes are played and grouped. Keeping a steady tempo is an important skill for musicians, but tempo can change depending on the music's style and how performers interpret it. Small or large changes in tempo are called "tempo rubato." In groups of musicians, tempo is often kept steady by following a conductor or a specific musician, such as the first violinist or drummer.

Measurement

Tempo can be described in many ways, such as with words like "Slowly," "Adagio," "Quickly," or "Allegro." However, it is most often measured in beats per minute (bpm or BPM). For example, a tempo of 60 beats per minute means one beat happens every second. A tempo of 120 beats per minute is twice as fast, with two beats happening every second. The note value of a beat is usually shown by the bottom number in the time signature. For instance, in 4/4 time, the beat is a quarter note.

Measuring tempo with beats per minute became more common in the early 1800s after Johann Nepomuk Maelzel invented the metronome. Beethoven was one of the first composers to use the metronome. In the 1810s, he included metronome markings for the eight symphonies he had written up to that time.

With modern technology, beats per minute became a very precise way to measure tempo. Music sequencers use the bpm system to show tempo. In popular music genres like electronic dance music, knowing a song's bpm is important for DJs to match beats correctly.

The speed of a piece of music can also be measured by how many measures or bars are played in one minute (mpm or bpm). This method is often used in ballroom dance music.

Choosing speed

In different musical situations, people like musicians, singers, conductors, bandleaders, music directors, or others choose the tempo of a song or piece. In a popular music or traditional music group or band, the bandleader or drummer may select the tempo. In popular and traditional music, whoever is setting the tempo often counts one or two bars to establish the speed. When a singer or solo musician starts with a solo part before the full group begins, the tempo they choose sets the tempo for the group.

In an orchestra or concert band, the conductor normally sets the tempo. In a marching band, the drum major may set the tempo. In a sound recording, sometimes a record producer may choose the tempo (though this is less common if the bandleader is experienced). Differences in tempo and how it is played can vary between cultures, as shown by Curt Sachs when comparing Tunisian and Western Classical music. Some music styles, like flamenco, have rhythmic changes that match their forms, known as palos.

Musical vocabulary

In classical music, people often describe the speed of a piece using words, usually in Italian, instead of or along with a metronome mark that shows beats per minute. Italian is commonly used because many composers in the past wrote in Italian, and these terms became standard in Western music. Well-known Italian tempo terms include "Allegro" (meaning cheerful), "Andante" (walking pace), and "Presto" (quickly). This practice began during the 17th and 18th centuries, known as the Baroque and Classical periods. Earlier, during the Renaissance, musicians played music at a tempo based on the tactus, which is roughly the human heartbeat. The time signature showed which note value matched the tactus.

During the Baroque period, music pieces were often labeled with a tempo term (like "Allegro") or the name of a dance (like "Allemande" or "Sarabande"), which also indicated tempo and rhythm. Musicians of that time were expected to understand these markings based on tradition. Sometimes, no markings were given. For example, the first movement of Bach’s Brandenburg Concerto No. 3 has no tempo or mood indication. Even with more explicit markings, musicians still follow conventions, such as expecting a minuet to be played slowly and a "perpetuum mobile" to be very fast. Genres suggest tempos. For example, Beethoven wrote "In tempo d’un Menuetto" over the first movement of his Piano Sonata Op. 54, even though that movement is not a minuet.

Many tempo terms also describe mood and expression. For instance, "Allegro" means fast and joyful, while "Presto" means fast but does not describe mood. Other terms like "agitato" (agitated) in George Gershwin’s piano concerto show both speed and emotion. Composers often name movements after their tempo or mood. For example, the second movement of Samuel Barber’s first String Quartet is called "Adagio."

Here is a list of common tempo terms. The beats per minute (bpm) values are rough estimates and vary depending on the composer. A metronome marking cannot be determined from a word alone. When both a metronome marking and a word are used, the word often adds style or feeling that a metronome cannot show.

Over time, the meanings of some terms have changed. For example, "Allegretto" originally meant slightly faster than "Andante," but now it is often slightly slower than "Allegro." Similar changes have occurred with "Adagietto," "Andantino," "Largo," and "Adagio."

Common Tempo Markings and Their Approximate BPM Ranges (for 4/4 time):
– Larghissimo – extremely slow (under 24 bpm)
– Adagissimo and Grave – very slow and solemn (24–40 bpm)
– Largo – slow and broad (40–66 bpm)
– Larghetto – rather slow and broad (44–66 bpm)
– Lento – slow (40–60 bpm)
– Adagio – slow with expression (44–66 bpm)
– Adagietto – slower than Andante or slightly faster than Adagio (46–80 bpm)
– Andante – walking pace, moderately slow (56–108 bpm)
– Andantino – slightly faster than Andante but slower than Moderato (80–108 bpm)
– Marcia moderato – moderately, like a march (66–80 bpm)
– Andante moderato – between Andante and Moderato (80–108 bpm)
– Moderato – moderate speed (108–120 bpm)
– Allegretto – moderately fast (112–120 bpm)
– Allegro moderato – close to Allegro (116–120 bpm)
– Allegro – fast and bright (120–156 bpm)
– Molto Allegro or Allegro vivace – faster and livelier than Allegro (124–156 bpm)
– Vivace – lively and fast (156–176 bpm)
– Vivacissimo and Allegrissimo – very fast and lively (172–176 bpm)
– Presto – very fast (168–200 bpm)
– Prestissimo – extremely fast (200 bpm and above)

Other Terms:
– A piacere or Ad libitum – performer may choose tempo and rhythm freely
– Accelerando – gradually faster
– Assai – very much
– A tempo – return to the original tempo
– Con Brio – with vigor
– Con grazia – gracefully
– Con moto – with movement (e.g., "Andante con moto")
– Furioso – furiously
– Lamentoso – sadly
– L'istesso tempo – same speed, even if time signatures change
– Ma non tanto – but not so much
– Ma non troppo – but not too much
– Maestoso – majestically
– Molto – very
– Meno – less
– Più – more
– Poco – little
– Rallentando – gradually slower
– Subito – suddenly
– Tempo comodo – at a comfortable speed
– Tempo di… – speed of a specific dance (e.g., "Tempo di valse" ≈ 60 or 126 bpm)
– Tempo giusto – consistent speed
– Tempo primo – return to original tempo
– Tempo semplice – simple, regular speed

Some composers used French terms, such as François Couperin, Jean-Philippe Rameau, Debussy, Ravel, and Satie. Common French terms include:
– Au mouvement – play the main tempo
– Grave – slowly and solemnly
– Lent – slowly
– Moins vite – less fast
– Modéré – moderate speed
– Vif – lively
– Très vif – very lively
– Vite – fast
– Rapide – rapidly

Many composers also used German terms, such as:
– Kräftig – vigorous
– Langsam – slowly
– Lebhaft – lively
– Mäßig – moderately

Variation through a piece

Tempo is not always the same throughout a musical piece. A composer may change the speed of the music completely, often by using a double bar line and introducing a new tempo instruction, which may include a new time signature or key signature.

A composer may also show a gradual change in tempo, such as speeding up (accelerando) or slowing down (ritardando). Some compositions, like Monti's Csárdás or the Russian Civil War song Echelon Song, are mostly made up of passages that gradually speed up.

On a smaller scale, tempo rubato refers to small changes in tempo within a musical phrase, often described as some notes taking time from others.

Composers may use expressive markings to adjust the tempo:

• Accelerando – speeding up (abbreviation: accel.); the opposite of ritardando. It is shown by gradually increasing the tempo until the next tempo mark is reached. It may be marked with a dashed line or its abbreviation.
• Affrettando – speeding up with a sense of urgency.
• Allargando – growing broader; slowing down, usually near the end of a piece.
• Calando – slowing down (and usually also becoming softer).
• Doppio movimento / doppio più mosso – double the speed.
• Doppio più lento – half the speed.
• Lentando – gradually slowing down and becoming softer.
• Meno mosso – slower.
• Meno moto – less motion.
• Più mosso – faster.
• Mosso – more lively; quicker, similar to più mosso but less extreme.
• Precipitando – hurrying; moving faster.
• Rallentando – gradually slowing down (abbreviation: rall.).
• Ritardando – slowing down gradually (abbreviation: rit.). Sometimes used instead of allargando.
• Ritenuto – slightly slower, achieved quickly. It may also refer to a change in character rather than tempo. (Abbreviation: rit. or riten.).
• Rubato – adjusting tempo for expressive purposes, literally "stolen" time.
• Slargando – gradually slowing down, literally "widening" or "stretching."
• Stretto – faster tempo, often near the end of a section. In fugal music, stretto refers to a specific technique and is not always about speed.
• Stringendo – pressing on faster, literally "tightening."
• Tardando – slowing down gradually (same as ritardando).
• Tempo Primo – returning to the original tempo.

The main tempo instruction (such as Allegro) is usually written in large letters above the musical staff. Adjustments, like accelerando or ritardando, are often written below the staff or in the middle of the staff for keyboard instruments.

For sudden tempo changes, composers usually write the new tempo directly. However, if Più mosso or Meno mosso is written in large letters above the staff, it acts as a new tempo, meaning an immediate change. Words like assai, molto, poco, and subito help describe how large or gradual a tempo change should be.

After a tempo change, a composer may return to a previous tempo in two ways:

• A tempo – returns to the original tempo after an adjustment (e.g., ritardando… a tempo undoes the ritardando).
• Tempo primo or Tempo I – returns to the original tempo after a section with a different tempo (e.g., Allegro… Lento… Moderato… Tempo I means returning to Allegro). This is often used as a structural marker in pieces with two parts.

These terms indicate immediate, not gradual, tempo changes. Although they are Italian, composers use them even if the original tempo was written in another language.

One challenge in defining tempo is that how we perceive it depends on rhythm, and how we perceive rhythm depends on tempo. This relationship is influenced by the context, as explained by Andranik Tangian using an example from Modest Mussorgsky's Pictures at an Exhibition.

In this example, a rhythm is perceived as it is, not as a repeated pattern at double speed. The way we perceive rhythm and tempo depends on how simple the pattern seems, as explained by the principle of correlative perception. This idea connects to Kolmogorov's complexity theory, which suggests that data is perceived in the simplest way possible.

The example shows two ways to interpret the same rhythm: either as it is or as a pattern involving tempo changes. The simpler interpretation uses less memory, making it easier to understand. In the musical example, the rhythm is recognized as repeated because the melody also repeats, adding redundancy that helps the rhythm stay clear even when tempo changes slightly. Generally, the more repeated or supported a rhythm is, the easier it is to recognize even when tempo changes.

Modern classical music

Twentieth-century classical music used many different ways to handle tempo, especially because of the influence of modernism and postmodernism.

Many composers continued to use traditional tempo markings, sometimes needing more precise instructions than in earlier times. However, some composers began to challenge basic ideas from the classical tradition, such as the belief in a steady, same, and repeatable tempo. Graphic scores display tempo and rhythm in many different ways. Polytemporal compositions intentionally have performers playing at slightly different speeds. John Cage's compositions use different methods for tempo. For example, 4′33″ has a set length, but no actual notes, while As Slow as Possible has set proportions but no set duration, with one performance planned to last 639 years.

Beatmatching

In music styles like disco, house, and electronic dance music, DJs use a technique called beatmatching. This involves adjusting the speed of a record or a CDJ player (a special CD player for DJs that can change speed) to match the tempo of another song. Once the tempos match, the DJ can smoothly transition between songs or play them together, creating a layered sound.

DJs often match the basic tempo of songs rather than the exact beats per minute (BPM) shown by the kick drum, especially with fast-paced tracks. For example, a song with 240 BPM can match a song with 120 BPM because both share the same basic tempo of 120 quarter notes per minute. This allows some soul music (75–90 BPM) to blend well with drum and bass (150–185 BPM). When adjusting a record's speed on a turntable, the pitch and tempo change together. Increasing the speed by 10% raises both pitch and tempo by 10%. Using software to change pitch without altering tempo is called pitch-shifting. Changing tempo without affecting pitch is called time-stretching.