Key

The key is the restricted area by the international governing body FIBA, and colloquially as the lane or the paint, is a marked area on a basketball court surrounding the basket. It is officially referred to as the free throw lane by the National Basketball Association (NBA), the National Collegiate Athletic Association (NCAA), and the National Association of Intercollegiate Athletics (NAIA). It is bounded by the endline, the free-throw line and two side lines (freebody lines), and usually painted in a distinctive color. It is a crucial area on the court where much of the game’s action takes place.

Dimensions of the key area have varied through the history of the game. FIBA rule amendments its shape is rectangular for games sanctioned by all three associations, 16 feet (4.9 m) wide for both NBA and FIBA keys, and 12 feet (3.7 m) for NCAA and NAIA keys.

The most-commonly enforced rule on the key is the “three seconds rule” in which the team of a player on offense who stays on the key for more than three seconds loses possession of the ball. Another rule is the lane violation which occurs if a player from either team enters the key before a free-throw shooter releases the ball in the act of shooting. There is also the restricted area arc directly underneath the basket where the defending player cannot force an offensive foul on the opposing player.

Each level of play has different specifications for the size and shape of the key: in American leagues, where the basketball court is measured in US units, the shape is rectangular, while in FIBA-sanctioned events, which use the metric system, the shape was trapezoidal before being changed to a rectangle as well. In addition to the bounding rectangle, the key includes a free-throw circle at its head or top.

The free throw circle has a 6-foot (1.8 m) radius centered at the midpoint of the free throw line. The half-circle on the mid-court side of the free throw line is painted solid. In the NBA and ULEB, the boundary of the half closer to the basket is traced in a broken line in order to space players properly for jump balls. NBA Rule 1 (g) requires the key to contain two 6-inch (15 cm) long hash marks, 3 feet (0.91 m) from the free throw line; the marks indicate the so-called lower defensive box.

The free throw line is 15 feet (4.6 m) from the perpendicular projection of the face of the backboard onto the court; this projection is 4 feet (1.2 m) from the end-line for NBA and NCAA or NAIA. The projection of the center of the basket onto the court is a perpendicular distance of 1.575 meters (5.17 ft) from the end line in FIBA tournaments, but 5.25 feet (1.60 m) in NBA and NCAA or NAIA tournaments.

Three-second violation

The lane is a restricted area in which players on offense (in possession of the ball) can stay for only three seconds. At all levels of play, after three seconds the player is assessed a three-second violation which results in a turnover.

In FIBA-sanctioned tournaments, defending team players are allowed to stay in the key with no time limit. In American professional basketball, defending team players are prohibited from staying in the key for more than three seconds, unless the player is directly guarding an offensive player. Otherwise if a defender exceeds that time, the defending team is charged with a defensive three-second violation, which results in a technical foul where the team with the ball is awarded one free throw, plus retaining possession and a reset of the shot clock. In all cases, the clock resets if the shot hits the rim or if the player steps out of the lane.

Lane violation

When a player is shooting free throws, a certain number of players are allowed at the boundaries of the key, each occupying a slot traced at the boundaries of the key. The free throw shooter is behind the free throw line, and in most leagues three of their opponents are along the sides of the key, one side with two players, the other with one. Two of their opponents are situated nearest to the basket on both sides, while their two teammates are beside the two opponents closest to the basket, with the other player from the opposing team situated farthest from the basket. In the U.S. NCAA and NAIA, there are as many as six players along the key, with the opposing team allowed to have as many as four players, with the same arrangement as in the NBA and FIBA but with another player facing their teammate farthest to the basket.

No player along the lane may enter the key until the shot is released. The player shooting the free throw, and anyone at top of the key, may not cross the free throw line until the ball hits the rim. If any of the offensive players violate the rule, no points are awarded for the shot and, if there are no more shots remaining, the ball is given to the defending team. If a defending player enters the lane too soon, an extra shot will be awarded regardless of whether the shot was made or missed.

In FIBA play, if the shooter commits the violation, it is an automatic turnover. If the shot is successful and the shooter does not commit a violation, but other players do commit a violation, all violations are dismissed. If players on the opposing team enter the key prior to the release of the ball, a jump ball determines who gets the possession of the ball (NBA) or the possession arrow rule (for all other levels). In FIBA play, that only applies if the shooter misses, since a successful attempt negates all other penalties. In all situations, lane violation penalties cannot occur if there are further free throws pending.

Restricted area arc

In the NBA, Euroleague, and in FIBA and NCAA or NAIA play, the key has an arc extending four feet from the basket (NBA and NCAA or NAIA), or 1.25 meters (approximately 4.1 feet) (FIBA). The area behind the arc, or the arc itself is called the “restricted area” (RA) in the NBA, the “restricted area arc” in the NCAA or NAIA and the “no-charge semicircles” in FIBA.

Its purpose is to prevent secondary defenders from taking a position under the basket in an attempt to draw an offensive foul while a player is driving to the basket. If a player on offense drives past their primary defender on the way to the basket and a secondary defender steps in, they must establish a position outside the RA to draw an offensive foul.

If the drive starts inside the Lower Defensive Box (LDB – the area from the bottom tip of the free throw circle to the end line between the two 3-foot posted-up marks), the secondary defender is allowed to be positioned inside the RA. The restricted area does not apply if the secondary defender jumps in attempting to block the shot, and the offensive player leads with their leg or knee in an unnatural motion or uses their off arm to prevent the defender from blocking their shot. The RA does not extend from below the backboard to the baseline. Therefore, if a player drives the baseline and is not attempting to go directly to the rim, the RA does not apply.

The NCAA moved the RA arc out to four feet from the center of the basket; the NAIA followed suit.

Points made on the key are termed as points in the paint or inside points. The area around the free throw circle’s farthest point from the basket is called the “top of the key”, and several plays revolve around this area, such as screens and pick and rolls.

The intersection of the free throw line and the free throw lane is referred to as the elbow of the key.