Allegro is a tempo marking meaning fast and lively. It comes from the Italian for cheerful. In practice, it covers a range of speeds, roughly 120 to 168 beats per minute. It is not as fast as presto. It is faster than andante. It is the tempo of a brisk walk, a lively conversation, a happy dance.

Composers use allegro for opening movements, finales, and anything that needs energy. Mozart's Eine kleine Nachtmusik opens with an allegro. Beethoven's Fifth Symphony opens with an allegro con brio, fast with vigor. The exact speed is up to the conductor. A metronome marking may be given, but the character matters as much as the number.

Tempo markings around allegro

• Largo: very slow, broad.
• Adagio: slow, at ease.
• Andante: walking pace.
• Moderato: moderate.
• Allegro: fast, lively.
• Presto: very fast.
• Prestissimo: as fast as possible.

Allegro is not just fast. It is cheerful. The mood matters. A fast piece can be aggressive, like a march. Allegro is bright, optimistic, energetic. It is the tempo of joy. That is why it is so common. Composers want to start with energy. They want to end with excitement. Allegro does both. It is the default fast tempo. When a composer writes allegro, the performer knows to play with spirit. Not rushed. Not frantic. Just lively. The Italian term captures something English cannot. Fast is a speed. Allegro is a feeling. That is why the Italian terms persist. They describe the music, not just the metronome.