Generally, it is considered proper concert etiquette to clap only after a piece is complete. Just like books have chapters and TV series have episodes, many orchestral pieces are divided into multiple sections called movements. Each movement can stand alone but contributes cohesively to the entire piece. Generally there are very brief pauses in between each movement, and the audience applauds at the conclusion of the work. You can tell how many movements a piece has by looking at your program. For example: Symphony No. 1 by Ludwig van Beethoven I. Adagio molto – Allegro con brio II. Andante cantabile con moto III. Menuetto: Allegro molto e vivace IV. Adagio – Allegro molto e vivace This symphony by Beethoven has four movements, so we can expect pauses between each movement and applause at the end of the last movement. Movement titles are often Italian terms for how fast the tempo will be or other characteristics. If you lose track of where the piece is, you can always wait for the rest of the audience to clap before applauding. Another good sign is when the conductor either turns around or steps off the podium.