Playing Rgulations
At the professional level, games are played in four quarters of 10 (international) or 12 minutes (NBA) each. Games take longer than this allotted game time, since the game clock only runs when the ball is in play. This is called using a stop clock, as the clock stops when the ball is not in play, for example, when it goes out of bounds or a foul is committed. Fifteen minutes are allowed at half-time, and two minutes are allowed at other intervals. At lower levels, various time regulations exist.

Time-outs and substitutions are permitted during a game. A substitution is that of one player on the court for another on the team bench. A time-out is a clock stoppage requested by the coach of either team, in which he can discuss tactics etc. A time-out lasts one minute in international basketball and either 100 seconds, 60 seconds or 20 seconds in NBA basketball. A limited number of time-outs is allowed. (In international basketball, 2 time-outs are allowed in the first two periods, 3 in the last two periods, and 1 in each extra period. In NBA basketball, six 100/60-second time-outs are allowed in the entire game of which a maximum of three can be in the last quarter, and 3 100/60-second time-outs in each extra period, as well as one 20-second time-out per half.)

Basketball Equipment
The only essential equipment in basketball is a court, two baskets with backboards and a basketball. At competition level, clocks are necessary to regulate game time. Professional and international games often call for more equipment, to assist in administration and officiating. This can include shot clocks, scorer's tables, and whistle-operated stop-clock systems.

The men's ball's circumference ranges between 749 and 762 mm (29.48 and 30 in); its diameter 238 to 242 mm (9.3 to 9.5 in). Its mass is from 567 to 624 g (1.246 to 1.374 lb). The smaller women's ball's circumference is between 724 and 737 mm (28.50 and 29.01 in), its diameter 230 to 235 mm (9.07 to 9.23 in), and its mass from 510 to 567 g (1.123 to 1.246 lb).

Playing the Ball
The ball may be advanced toward the basket by being shot, passed, thrown, tapped, rolled or dribbled. Passing is throwing the ball from player to player. Dribbling is when a single player runs while continuously bouncing the ball. The ball cannot be kicked deliberately or struck with the fist, and must stay within the playing court.

Running with the ball without bouncing it, or travelling is illegal; as is double dribbling, the act of dribbling with two hands or starting a second dribble after having caught the ball after a first one. A player's hand cannot pass the vertical while dribbling, so that his hand is partially below the ball; this is known as carrying the ball. In higher levels of basketball time limits are imposed on advancing the ball past halfway, remaining in the restricted area (also known as the "paint") and attempting a shot. Rules with playing the ball are stricter in the NBA. Contrary to popular belief, there is no limit to the amount of steps a player can take between bounces while dribbling.