How does match time works in soccer?
I think I know a little bit about how it works, like how they add injury time to the end of the regular time, but I do not know it for sure.
The duration depends on the referee. Injury time is established by the referee and he gives how many minutes of stoppage time he wants.
From the "Laws of the Game":
As you probably knew already, any kind of match interruptions will extend the stoppage time. However, only the referee can be the timekeeper.
Facts: The ball is in game for about 22 minutes each half in the most important leagues. The longest injury time given was 23 minutes. Germany referees usually give no more than 3 minutes of additional time.
Well the regular amount of time for each half normally lasts 45 minutes:
Injury Time is added at the end of each half:
And in certain competitions, Extra Time may be required at the end of a game, for example in the World Cup, where two halves of 15 minutes in length are played, with the above rules of added time applying to those two halves.