Basketball Court Lines: Names, Dimensions, and Rules Explained

A regulation basketball court has 10 distinct lines and markings, each with a specific name and gameplay purpose. The main basketball court lines are: sidelines, endlines (baselines), the mid-court line, the center circle, the free throw line, the three-point line, the key (lane) boundaries, lane space marks, the no-charge arc, and various hash marks for officials. All standard lines are 2 inches wide.

What Are the Lines on a Basketball Court?

Here's a quick breakdown of every major line, what it does, and whether it counts as in-bounds or out-of-bounds. This answers the most common version of the search — players, coaches, and facilities teams all need the same basic map.

As noted in the Wikipedia overview of basketball courts, court sizes and line placements vary across the NBA, FIBA, WNBA, and NCAA — but the fundamental set of markings is consistent across all levels.

The Boundary Lines

These are the lines that define where the court ends. Step on them or past them — you're out of bounds. Simple in theory, occasionally contested in practice.

Sidelines

The sidelines run the full length of the court on both sides. On NBA and NCAA courts, they stretch 94 feet (28.65 m). On FIBA and Olympic courts, that drops slightly to 28 meters (91 ft 10 in). High school courts are shorter — 84 feet (25.6 m).

A player, ball, or pass that touches the sideline is immediately out of bounds. The line itself is out of bounds, not in. In practice, referees track foot placement carefully on sideline calls — it's one of the most reviewed situations in instant replay.

Endlines / Baselines

The short lines running behind each basket are called endlines — or baselines, depending on context. Both terms refer to the same line. The distinction is mostly positional: it's an endline when referenced in terms of court boundaries (such as inbounding after a made basket), and a baseline when describing offensive positioning or drives.

On standard senior courts, endlines are 50 feet (15.24 m) wide. Like the sideline, the endline itself is out of bounds.

Mid-Court Line (Half-Court Line)

The mid-court line bisects the court horizontally, splitting it into the frontcourt and backcourt. It doesn't look like much, but it carries real weight in gameplay.

Once an offensive team advances the ball across the mid-court line, they cannot return it to the backcourt — doing so triggers a backcourt violation. In the NBA, the offensive team must cross the line within 8 seconds of gaining possession. NCAA rules use the same 8-second standard.

Interestingly, this line is treated as out of bounds for the ball in transition — a ball sitting on the line counts as backcourt.

The Key, Free Throw Lane, and Associated Markings

The key is arguably the most action-dense zone on any basketball court. It goes by several names — the key, the lane, the paint — and has more sub-markings than any other part of the court.

The Key / The Paint

The key is the rectangular zone extending from the endline to the free throw line beneath each basket. It's called "the paint" because it's almost always painted a contrasting color — this isn't a rule requirement, but it's universal practice in professional and collegiate courts.

Key width varies noticeably across leagues:

The NBA's wider key reflects a deliberate design decision — a wider lane creates more driving room and reduces low-post congestion. In the NBA, a defensive player not actively guarding an opponent can only remain in the key for 3 consecutive seconds. NCAA and FIBA don't have this defensive 3-second rule, which allows teams to station a rim-protector in the paint.

Free Throw Line

The free throw line runs parallel to the endline and marks where players stand for foul shots. In all major leagues — NBA, NCAA, FIBA, and high school — the standard distance is 15 feet from the face of the backboard (the NBA rule sets this at 15 ft exactly; FIBA uses 15 ft 1 in / 4.60 m).

The line is in bounds. Players attempting free throws must stay behind it until the ball hits the rim.

Lane Space Marks and Hash Marks Along the Key

These are the small rectangular marks lining both sides of the key. They look decorative from a distance. They're not.

During free throw attempts, players waiting to rebound must stand in designated spots along the lane. Each mark — 2 inches wide and 6 inches long per NBA specifications — indicates an assigned position. The areas marked out are for alternating defensive and offensive players.

What's often overlooked is that the lane space marks themselves are not boundary lines. A player standing on them is in bounds.

No-Charge Arc (Restricted Area)

The no-charge arc is a semi-circle painted inside the key, directly under the basket. The NBA introduced it in 1997; FIBA adopted a version as well.

Its purpose is specific: it stops defensive players from drawing offensive charging fouls by stationing themselves directly under the basket. If a defender is standing inside the arc and an offensive player collides with them, the defensive player cannot be awarded a charge — it's called a blocking foul instead.

The Three-Point Line

The three-point line is probably the most strategically significant marking on the court today. It's not a simple arc — it has two components.

Along most of the perimeter, it forms a curved arc at a set distance from the basket. But near the corners, it straightens into two parallel lines running from the baseline inward. This creates the "corner three" — a shorter shot that coaches and analysts actively design plays around.

According to the Wikipedia article on the three-point field goal, the distance from the basket to the three-point line varies significantly by competition level — from 23 ft 9 in in the NBA down to 19 ft 9 in in high school play.

The NBA actually shortened the three-point line during the 1994–1997 seasons — reducing the arc distance to 22 feet across to encourage more three-point attempts and higher-scoring games. It was returned to 23 ft 9 in after scoring didn't increase as expected.

A shot attempted with a player's foot on the three-point line counts as a two-point field goal, not three. The player must be fully behind the line.

The Center Circle

The center circle sits at the exact midpoint of the court. It's used for the opening tip-off at the start of each game and for jump balls when required.

During tip-off, one player from each team stands inside the circle. All other players must remain outside the circle until the ball is tapped. The mid-court line runs through the circle's center.

Official and Administrative Court Markings

These markings don't directly affect scoring or player positioning during live play, but they're required by league rules and serve referees, coaches, and game administrators.

Coaching Box Lines

The coaching box is marked along the sideline near each team's bench. It defines the area where coaches are permitted to stand and move during the game. In the NBA, coaches must remain within this zone unless they step out for specific reasons allowed under league rules.

Substitution Box Markings

Per NBA rules, two hash marks are drawn perpendicular to the sideline, 4 feet on each side of the mid-court line, in front of the scorer's table. This designates the substitution box — the area where players wait before entering the game.

Mid-Court Hash Marks (28 ft Marks)

Four hash marks are drawn 28 feet from the baseline, perpendicular to the sideline, on each side of the court. Each extends 3 feet onto the court. These are used by officials as reference points and help crews track positioning during specific game situations.

How Basketball Court Lines Differ Across Leagues

Most casual players assume courts are uniform. At first glance they look it, but the differences between an NBA court and a high school court are meaningful — especially for players transitioning between levels.

Half-Court and Recreational Court Lines

Half-court games skip the mid-court line as a functional boundary and use one basket. A standard half-court on an NBA layout measures 47 ft × 50 ft (14.33 m × 15.24 m). All other markings — the key, free throw line, three-point line, and center circle — remain the same on the active half.

For backyard or gym setups, the lines that matter most are the three-point arc, the key boundaries, and the free throw line. These three define the game. The rest — substitution boxes, hash marks, coaching lines — are administrative and not needed for recreational play.

Conclusion

Basketball court lines divide the court into clearly defined zones that govern scoring, player positioning, and game flow. The key lines — boundary lines, the free throw line, the three-point arc, and the no-charge arc — vary slightly across NBA, NCAA, FIBA, and high school courts. Knowing what each line means makes the game easier to follow and play correctly.

Frequently Asked Questions

Are boundary lines in bounds or out of bounds in basketball?

Boundary lines — sidelines and endlines — are out of bounds. Any player, ball, or pass that touches these lines is immediately dead. The line itself is not in-bounds territory.

What is the paint in basketball?

The paint refers to the key — the rectangular zone below each basket, usually painted a contrasting color. It runs from the endline to the free throw line and is 16 ft wide in the NBA, 12 ft wide in NCAA and high school.

What is the no-charge arc used for?

It prevents defenders from drawing charging fouls by standing directly under the basket. If a defender is inside the arc when contact occurs, it is ruled a blocking foul, not a charge.

How wide is the three-point line distance in the NBA vs. high school?

The NBA three-point arc sits 23 ft 9 in from the basket. High school courts use 19 ft 9 in. NCAA sits at 22 ft and FIBA at 22 ft 2 in.

What is the mid-court line used for?

It separates the frontcourt from the backcourt. Once the offense crosses it, they cannot return the ball to the backcourt — doing so is a violation. The offense has 8 seconds to cross it in NBA and NCAA play.