Saxophones can have anywhere from 20 to 23 keys on average. A beginner alto saxophone, for example, may have closer to 20 keys because it doesn't have advanced features. However, an advanced baritone saxophone may have keys to produce both a low A and a high F sharp. It could easily have 23 keys. Luckily, you don't need to have 20 to 23 fingers to play all of the notes. Some keys, like the F, E, and D keys, trigger a second key to close with it.