How Much Time is Really Left in the Basketball Game?
Based on three nationally televised NBA playoff games, a professional basketball game lasts for an average of 148 minutes. The TNT network schedules 2½ hours of airtime for their broadcast.

Here's how it breaks down by quarter:

If you are like me, trying to schedule the remains of your evening, the fourth quarter can surprise you with its length. I measured fourth quarters as long as 40 minutes in duration.

The average was 36.6 minutes, or three times the time on the game clock.

This ratio of clock time to real time depends on how close the game score is. Close games tend to last longer as every possession is closely planned, requiring more time outs and video replay reviews by the referees.

Splitting the final period into four three-minute segments, they last for an average of 6, 11, 9 and 8 minutes, respectively. These measurements allowed me to make a final countdown for the game, shown below.

This breakdown reveals a slightly shorter average time for the fourth quarter (34 vs. 36 minutes) due to a different group of basketball games in the sample set.

Hopefully these charts will help you to predict the precise end of basketball games, putting to rest wild exagerations of supernaturally short and excruciatingly long game ends.

The confusion lies with the games using "minutes" in a way which doesn't fit with the way everyone else uses time. In my opinion, game clocks should be marked with a different unit than seconds and minutes. I propose "gameticks", "super-minutes" or "triple secs".