How Long Is An NBA Game?

An NBA game consists of four quarters, each lasting 12 minutes, making the whole game 48 minutes long. Because the clock stops every time the game stops, the game does not last 48 minutes exactly. In summation, the entire game lasts around 2-3 hours with the clock stoppings.

The stopping of the clock applies to a situation when a foul has been committed, a timeout has been called, a free throw is being shot, or a player or the ball is out of bounds. There are also commercials and halftime, which lasts 15 minutes, and breaks between the first and second quarter and third and fourth quarter in a duration of 5-30 minutes. 

That is why watching the match broadcast makes it seem longer, but in reality, the playing part of the game lasts 48 minutes + overtime, if necessary.