Measurements and time limits discussed in this section often vary among tournaments and organizations; international and NBA rules are used in this section.
The object of the game is to outscore one’s opponents by throwing the ball through the opponents’ basket from above while preventing the opponents from doing so on their own. An attempt to score in this way is called a shot. A successful shot is worth two points, or three points if it is taken from beyond the three-point arc which is 6.25 meters (20 ft 6 in) from the basket in international games and 23 ft 9 in (7.24 m) in NBA games.
Games are played in four quarters of 10 (international) or 12 minutes (NBA). Fifteen minutes are allowed for a half-time break, and two minutes are allowed at the other breaks. Overtime periods are five minutes long. Teams exchange baskets for the second half. The time allowed is actual playing time; the clock is stopped while the play is not active. Therefore, games generally take much longer to complete than the allotted game time, typically about two hours.
Five players from each team may be on the court at one time. Teams can have up to seven substitutes. Substitutions are unlimited but can only be done when play is stopped. Teams also have a coach, who oversees the development and strategies of the team, and other team personnel such as assistant coaches, managers, statisticians, doctors and trainers.
For both men’s and women’s teams, a standard uniform consists of a pair of shorts and a tank top with a clearly visible number, unique within the team, printed on both the front and back. Players wear high-top sneakers that provide extra ankle support. Typically, team names, players’ names and sometimes sponsors are printed on the uniforms.
A limited number of time-outs, clock stoppages requested by a coach for a short meeting with the players, are allowed. They generally last no longer than one minute unless, for televised games, a commercial break is needed.
The game is controlled by the officials consisting of the referee, one or two umpires and the table officials. The table officials are responsible for keeping track of each teams scoring, timekeeping, individual and team fouls, player substitutions, team possession arrow, and the shot clock.
A diagram of a FIBA basketball court.
The only essential equipment in basketball is the ball and the court: a flat, rectangular surface with baskets at opposite ends. Competitive levels require the use of more equipment such as clocks, scoresheets, scoreboards, alternating possession arrows, and whistle-operated stop-clock systems.
The men’s ball’s circumference is about 30 inches (76 cm) and weighs about 1 lb 5 oz (600 g). The women’s ball’s circumference is about 29 inches (73 cm) and weighs about 1 lb 3 oz (540 g). A regulation basketball court in international games is 28 by 15 meters (approx. 92 by 49 ft) and in the NBA is 94 by 50 feet (29 by 15 m). Most courts are made of wood.
A cast-iron basket with net and backboard hang over each end of the court. At almost all levels of competition, the top of the rim is exactly 10 feet (3.05 m) above the court and 4 feet (1.2 m) inside the endline. While variation is possible in the dimensions of the court and backboard, it is considered important for the basket to be the correct height; a rim that is off by but a few inches can have an adverse effect on shooting.
The ball may be advanced toward the basket by being shot, passed between players, thrown, tapped, rolled or dribbled (bouncing the ball while running).
The ball must stay within the court; the last team to touch the ball before it travels out of bounds forfeits possession. The ball-handler may not move both feet without dribbling, known as traveling, nor may he dribble with both hands or catch the ball in between dribbles, a violation called double dribbling. A player’s hand must remain on top of the ball while dribbling, failure to do so is known as carrying the ball. A team, once having established ball control in the front half of the court, may not return the ball to the backcourt. The ball may not be kicked nor struck with the fist. A violation of these rules results in loss of possession, or, if committed by the defense, a reset of the shot clock.
There are limits imposed on the time taken before progressing the ball past halfway (8 seconds in international and NBA), before attempting a shot (24 seconds), holding the ball while closely guarded (5 seconds), and remaining in the restricted area (the lane, or “key”) (3 seconds). These rules are designed to promote more offense.
No player may interfere with the basket or ball on its downward flight to the basket, or while it is on the rim (or, in the NBA, while it is directly above the basket), a violation known as goaltending. If a defensive player goaltends, the attempted shot is considered to have been successful. If a teammate of the shooter goaltends, the basket is cancelled and the team loses possession.
The referee signals that a foul has been committed.
An attempt to unfairly disadvantage an opponent through personal contact is illegal and is called a foul. These are most commonly committed by defensive players; however, they can be committed by offensive players as well. Players who are fouled either receive the ball to pass inbounds again, or receive one or more free throws if they are fouled in the act of shooting, depending on whether the shot was successful. One point is awarded for making a free throw, which is attempted from a line 4.5 metres (15 feet) from the basket.
There is some discretion with the referee when calling a foul — referees consider if there was unfair advantage gained, e.g. if a player were to gain possession unfairly, sometimes making fouls controversial calls. The calling of a foul can vary between games, leagues and even between referees.
A player or coach who shows poor sportsmanship, for instance, by arguing with a referee or by fighting with another player, can be charged with a technical foul. The penalty involves free throws and varies between leagues. Repeated incidents can result in disqualification. Blatant fouls with excessive contact or that are not an attempt to play the ball are called unsportsmanlike fouls (or flagrant fouls in the NBA) and incur a harsher penalty; in some rare cases a disqualifying foul will require the player to leave the playing area, known as an ejection.
If a team surpasses a preset limit of team fouls in a given period (quarter or half) – four for international and NBA games – the opposing team is awarded one or two free throws on all subsequent fouls for that period, the number depending on the league. A player who commits five fouls, including technical fouls, in one game (six in some professional leagues, including the NBA) is not allowed to participate for the rest of the game, and is described as having “fouled out”.