Many tournaments feature cuts, usually at the midway point in the tournament. After two rounds of a 4-round tournament, for example, the field might be cut, with the bottom half being sent home and the top half continuing through rounds three and four.
The cut line is the score that players must have in order to continue playing. For example, if the cutline is +4, then all golfers in the tournament who are at +4 or better continue; those higher than +4 are cut from the field.
The cut line is a fluid number that changes depending on how well, or poorly, the field is scoring. The cut line is never specifically known prior to a tournament's start. It is usually determined by announcing the number of places in the field that will constitute the cut line.
For example, if there are 144 players in a field, the cut line might be announced as the top 60 players plus ties, along with all golfers within 10 shots of the lead. As the tournament progresses, the specific score required to make the cut will change based on the scores of the players who meet the criteria of the cut line. This is why, in broadcasts of tour events, the cut line might be show as changing from +3 to +4 to +5 over time.
