How is soccer timed?

Answer 1

The time is kept by the (center) referee, and his watch is the only one that matters. Assistant referees, fourth officials, competition authorities, broadcast affiliates, stadium scoreboards, and spectators (including coaches) may also keep the time as a back-up, but in the end, only the referee's watch matters.

Most matches are played with two 45-minute halves and a 15-minute intermission. Variations exist for youth, women, disabled, veteran, and indoor players. There may be two additional 15-minute periods in some competitions, as well as time taken for Kicks from the Penalty Mark. All periods of play may have time added to account for injuries, substitutions, time-wasting, or other delays that may occur.

The clock runs continuously in soccer; it does not stop when the ball goes out of play (like NFL football). Instead, time is added to the end of the period by the referee to account for delays (as mentioned above). The referee alone decides how much time is to be added, and will let everyone know in no uncertain terms when he has decided that the time has expired.