Even if the actual start-to-finish time in real life will be different for each NFL game, the clock is supposed to only run for 60 minutes.
Depending on the number of time outs, the speeds of the offences or how often the ball is run rather than passed, the time it takes to exhaust the 60 minutes of the game clock will vary, but most contests are over once the clock hits double zeros.
Unless, of course, the two teams are tied. Then, that brings about overtime and even double overtime if necessary.
Therefore, there have been some NFL games with the game clock running well over 60 minutes and here comes a look at the longest ever.
The NFL's longest ever game: Dolphins vs Chiefs in 1971
The longest the clock has ever been running in an NFL game was the clash between the Miami Dolphins and the Kansas City Chiefs in the 1971 AFC Divisional round, taking place on Christmas Day of 1971.
On that occasion, the two sides had to go to double overtime and they recorded the longest ever NFL game time of 82 minutes and 40 seconds.
A back-and-forth second half meant that the game finished 24-24, requiring overtime to determine a winner.
The first 15 minutes of overtime produced no more points, and it took until around halfway through the second overtime period for the breakthrough to come.
Garo Yepremian then stepped up and kicked a 37-yard field goal to give the Dolphins the 27-24 victory.
"On the sideline, I was dying for the chance to take the kick and, after I kicked the ball, I looked up at the sky and thanked God for giving me the chance to kick it."
That memorable game smashed the previous record, which had been the 77 minutes and 54 seconds of a Texans vs Oilers game in 1962.
