In soccer (football), goals against average (GAA) calculates as follows:
Goals Against Average = (goals against x game length) / minutes played.
If a goalie has been in net for 977 minutes, has allowed 18 goals in that time, and regulation time for the league they play in is 90 minutes per game:
18 goals against times 90-minute game length is 1,620.
1,620 divided by 977 minutes played is 1.658
Therefore, the goalie’s Goals Against Average (GAA) is is1.658
Goals Against Average is a statistic in used in soccer football (as well as ice hockey, field hockey, lacrosse, water polo and other sports with a goalie) that is used to put a goalie’s number of goals allowed into perspective with their total playing time.
It is intended to give a measure of how many goals the goalie allows per unit of regulation game time.
It is considered one statics among some other ones, including win/loss ratio and save percentage that are used to help measure a goalie’s capability.
What counts as a “Goal Against”?
In soccer, a “goal against” is a goal that occurs while the goalie is assigned the position of the goalkeeper.
If the goalie is not on the field of play at the time when the goals happen, a goal against the team does not count against the goalie’s GAA.
Rules for what qualifies as a goal can be found in the FIFA laws of the game (other leagues with alternative rules may have different scoring regulations).
What counts as a “Minute Played”?
Each minute that the goalie is an active player in a game counts as a “minute played.”
What is “Game Length”?
Game length varies depending on the league.
FIFA level matches have a game length of 90 minutes (2 halves of 45 minutes). Recreational leagues may have shorter halves.
- Wikipedia – Goals Against Average (GAA)
- FIFA – Laws of the Game
- Wikipedia – Goalkeeper (Association Football)
- MLS Soccer – Player Stats (season)