NBA Rules Explained: Shot Clock, Fouls, Free Throws and the Calls Fans Argue About

The NBA is the fastest major sport to pick up, but a handful of rules shape every possession, and they cause most of the arguments at the bar. Here are the NBA rules that matter most, explained simply.

Game Length and Overtime

• Four quarters of 12 minutes, 48 minutes of game time
• A halftime break after the second quarter
• Overtime: if the game is tied, teams play 5-minute periods until someone wins. There are no ties in the NBA.

Thanks to timeouts, fouls and reviews, a game usually takes about two and a half hours in real time.

The Shot Clock: 24 Seconds

Each possession has a 24-second shot clock. The offense must attempt a shot that hits the rim before it expires, or it loses the ball.

• The clock resets to 24 when possession changes.
• It resets to 14 after an offensive rebound off the rim, and on some fouls.

The shot clock is why NBA games are so fast and high-scoring.

Time Rules: 8 Seconds and 3 Seconds

• 8-second rule: after gaining possession in the backcourt, the offense has 8 seconds to bring the ball past half court.
• Backcourt violation: once the ball crosses half court, the offense cannot take it back.
• Offensive 3 seconds: an offensive player cannot stand in the lane, the painted area under the basket, for more than 3 seconds at a time.
• Defensive 3 seconds: a defender cannot stay in the lane for more than 3 seconds unless closely guarding an opponent. This rule is unique to the NBA and keeps big men from simply parking under the rim.

Traveling and Dribbling

• Traveling: a player holding the ball can take two steps before passing or shooting. The famous "gather step" is the moment a player picks up the ball, and it does not count as one of the two.
• Double dribble: a player cannot dribble, stop and then dribble again, or dribble with both hands at once.
• Carrying: the hand cannot go under the ball while dribbling.

Fouls

Personal fouls are illegal contact: holding, pushing, hacking or blocking a moving player.

• A player who commits six personal fouls fouls out and must leave the game.
• Charging vs. blocking: if a defender establishes legal position before the offensive player starts the shooting motion, the offensive player is called for a charge. If the defender is still moving or under the basket in the restricted area, it is a blocking foul.
• Technical fouls are for unsportsmanlike conduct and give the other team one free throw. Two technicals mean an ejection.
• Flagrant fouls are unnecessary or excessive contact and lead to free throws plus possession, and sometimes an ejection.

Free Throws and the Bonus

A player fouled while shooting gets free throws: two for a missed two-point shot, three for a missed three, and one if the shot goes in (the "and-one").

Non-shooting fouls usually just give the ball back to the offense, until the defense hits the bonus:

• Once a team commits five team fouls in a quarter, every defensive foul sends the opponent to the line for two free throws.
• In the last two minutes of a quarter, a team that has not reached the limit goes into the bonus on its second foul.

That is why you see intentional fouling late in close games.

Goaltending

Goaltending is touching a shot on its way down toward the basket, or touching the ball while it is directly above the rim. The basket counts automatically. Basket interference is the same idea for touching the rim or net during a shot.

Coach's Challenge

Each coach can challenge a call, such as a foul or an out-of-bounds decision, by calling a timeout. Officials then review the play on video.

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