When attending a classical music performance, novice guests often worry about when to clap. These are the times when applause is appropriate:
When the conductor steps on the platform and raises his or her baton, all clapping ceases, and the audience becomes silent. At performances by ensembles and soloists, watch the performers carefully; they signal by gesture and mood when they are ready to begin.
It's sometimes hard to know a piece has ended because there's usually a pause between movements and you may think the piece is over. One suggestion is to count the number of movements listed in the program and applaud only when the last movement is completed. The conductor may turn immediately to the audience, but some don't, so if you aren't sure the piece is over, follow the audience's lead. The audience may not always be right, but at least you won't be clapping by yourself.
The conductor will turn to the audience and bow and may point out members of the orchestra for recognition. Guest artists and occasionally composers will come to the stage for more applause. Don't rush for the exit at intermission or the end of the performance; remain seated until the clapping begins to die down and the people around you start to move.
Note: Although the mood and manners are less restrained at pop concerts and audience participation is often part of the program, the concert manners above still apply.