Basketball Court Lines: Every Marking, Name, and Dimension Explained

Basketball court lines define where the game is played, how shots are scored, and where players can legally stand. Every line on a court serves a specific purpose — from the boundary lines that keep the ball in play to the small hash marks most people never think about. Dimensions vary by level, but the logic behind each marking stays consistent.

What Are the Lines on a Basketball Court?

A standard basketball court has four categories of lines: boundary lines (sidelines and baselines), scoring reference lines (three-point arc and free throw line), lane markings (the key, paint, and blocks), and secondary markings (hash marks, substitution box, restricted area arc).

Together, these basketball court lines govern almost every rule decision a referee makes during a game — out-of-bounds calls, shot values, free throw violations, and charging fouls all depend on where a player or the ball is relative to a specific line.

What's often overlooked is that some "lines" don't physically exist on the floor at all. The free throw line extended, for example, is purely a coaching concept — no paint, no marking, just a shared reference point.

Why Basketball Court Lines Matter

Lines aren't decoration. Each one is tied directly to a gameplay rule. Remove the three-point arc and scoring logic collapses. Remove the restricted area and defenders could legally stand under the basket drawing charges all game. In practice, understanding what each line does helps players, coaches, and even spectators follow the game more clearly.

The Boundary Lines

Sidelines

The sidelines are the two lines running the full length of the court. They mark the outer boundary on each long side. On NBA and NCAA courts, sidelines run 94ft (28.65m). High school courts are shorter — 84ft (25.60m). Any player or ball touching or crossing a sideline is ruled out of bounds immediately.

Baseline and Endline

Here's something that trips people up: baseline and endline refer to the same physical line. The difference is context.

When a team is on offense, the line behind their basket is called the baseline. When they're defending that same end, it becomes the endline. Both run 50ft (15.24m) wide on standard courts and sit 4ft behind each basket.

The Mid-Court Line

The mid-court line splits the court exactly in half. It runs parallel to the baselines across the full 50ft width.

Offensively, it functions as a one-way boundary. Once the ball crosses into the front court, it cannot legally return to the back court — that's a backcourt violation. Most levels also require the offensive team to advance the ball past this line within 8–10 seconds of gaining possession.

Front Court and Back Court

The mid-court line creates two distinct zones.

The front court is the offensive half — from the mid-court line to the baseline. The back court is everything behind the mid-court line on the defensive side. Once the ball is advanced into the front court, it's locked there for that possession. Going back across the line, intentionally or not, turns the ball over.

The Key (Free Throw Lane)

The key — also called the lane, or the paint — is the rectangular area stretching from the baseline to the free throw line at each end of the court. It's usually painted a contrasting color, which is exactly why it's called "the paint."

As according to Wikipedia, the key is officially referred to as the free throw lane by the NBA, NCAA, and NFHS, though FIBA uses the term "restricted area" for the same zone.

Lane Lines

The lane lines form the sides of the key. Their width varies noticeably by level:

NBA and FIBA: 16ft (4.88m) wide
NCAA and high school: 12ft (3.66m) wide

Each lane line is 2" wide and runs from the baseline to the free throw line. Along these lines are lane space markings — small 2"×6" blocks that tell non-shooters exactly where to stand during a free throw attempt. The first space on each side is reserved for the team opposing the shooter.

What's easy to miss is that the lane space markings themselves are not boundary lines. Neither are the neutral zone marks between them — the NBA rulebook specifically clarifies this distinction.

The Free Throw Line

The free throw line sits 15ft from the backboard (15ft 1" in FIBA). It's drawn 2" wide, parallel to the baseline, and marks where a player stands during a free throw attempt. The shooter cannot step on or cross this line until the ball makes contact with the rim.

The free throw line also defines the top edge of the three-second area.

The Three-Second Area (The Paint)

The paint is the rectangle enclosed by the lane lines, free throw line, and baseline. Offensive players cannot remain in this area for more than three consecutive seconds — it's one of the more commonly called violations at every level.

The NBA also enforces a defensive three-second rule, meaning defenders can't camp in the paint either unless they're actively guarding someone. NCAA and FIBA do not apply this rule to defenders, which meaningfully changes how zone defense is played at those levels.

The Block

The block is the rectangular marking painted on each lane line, close to the basket. During a free throw, it's a designated alignment spot — the first lane space position. During live play, it's one of the most contested spots on the court. A player who establishes position on the block — offense or defense — has a clear positional advantage for post play and rebounding.

The Elbow

The elbow is where the free throw line meets the lane line. There are two elbows per basket — one on each side. It's not a painted marking on its own, but it's one of the most referenced spots in basketball strategy. Coaches use it constantly.

Dribble penetration to the elbow, offensive sets run from the elbow, defensive positioning relative to the elbow — it comes up constantly in practice.

The Free Throw Circle

The free throw circle has a diameter of 12ft (3.66m) on NBA and NCAA courts, slightly smaller at 11ft 10" (3.60m) under FIBA rules. It's centered on the free throw line.

During a free throw, the shooter must stay inside the circle until the ball contacts the rim.

During jump ball situations, all players who aren't jumping must remain outside the circle until one of the jumpers taps the ball.

The Three-Point Line

The three-point line — more precisely, the three-point arc — determines whether a made field goal is worth two or three points. Any shot released with both feet behind this line scores three. One foot on or inside the line means two points.

The distances vary by level, and as according to Wikipedia, the arc distance from the center of the basket differs across every major governing body:

NBA: 23ft 9" (7.24m) from the basket at the top of the arc; 22ft (6.71m) in the corners
NCAA Men: 20ft 9" (6.32m)
FIBA: 20ft 6" (6.25m)
High School: 19ft 9" (6.02m)

The corner distance in the NBA is worth noting. The arc geometry physically can't maintain 23ft 9" all the way to the sideline — the court isn't wide enough. So at each corner, the line runs as a straight parallel line 3ft from the sideline instead of continuing the arc. This is why the corner three is considered a more efficient shot — same three points, shorter distance.

The Center Circle

The center circle sits at the exact midpoint of the court. It has a diameter of 12ft (3.66m) on NBA and NCAA courts and 11ft 10" (3.60m) under FIBA rules.

Its primary use is the opening tip-off. At the start of each game, one player from each team stands inside the circle while the referee tosses the ball up. All other players must remain outside the circle until one of the jumpers makes contact with the ball. The same rule applies during any jump ball situation called during the game.

Hash Marks and Secondary Markings

Most people can identify the three-point line and the paint. The hash marks? Far less discussed — but they matter.

Sideline Hash Marks

Four hash marks sit perpendicular to each sideline, 28ft from the baseline. Each extends 3ft onto the court and is drawn 2" wide. These marks serve as reference points for officials and players during throw-ins and certain positioning situations.

Free Throw Lane Hash Marks

There are two sets of these:

Baseline hash marks — positioned 3ft from each lane line, extending 6" onto the court
Free throw circle hash marks — positioned 13ft from the baseline, 3ft from each lane line, also 6" in length

Both are drawn 2" wide. They help align players and officials during free throw attempts and aren't commonly noticed until you know what to look for.

Substitution Box Markings

Two hash marks are drawn perpendicular to the sideline, 4ft on each side of the mid-court line. This designated area is where substitute players wait before entering the game. It keeps the substitution process organized and gives officials a clear visual reference.

The Restricted Area (No-Charge Arc)

The restricted area is the semi-circular arc painted under each basket. On NBA and NCAA courts, it has a radius of 4ft from the center of the basket ring. FIBA sets this at 4ft 1" (1.25m).

The arc was introduced in the NBA in 1997 to address a specific problem: defenders positioning themselves directly under the basket with the sole intent of drawing charging fouls from driving offensive players. If a defender is standing inside this arc when contact occurs, they cannot be awarded a charge — it's a blocking foul instead.

In practice, this rule significantly changed how defenders position themselves near the rim and how aggressively guards drive to the basket.

Coaching and Strategic Reference Lines

Not everything called a "line" in basketball is actually painted on the court.

Top of Circle (Key)

The top of circle refers to the area just outside the free throw circle, directly in front of the basket. There's no painted marking here — it's a positional reference coaches use to set offensive alignments and define where the ball-handler should operate at the top of a play.

Free Throw Line Extended

This one confuses a lot of people. The free throw line extended is completely imaginary — no paint, no physical marking. It's the conceptual extension of the free throw line across the full width of the court. Coaches use it to divide the court into zones: different defensive rules and offensive alignments apply depending on whether the ball is above or below this invisible reference.

Wing Areas

Wing areas sit on each side of the court near the free throw line extended. The side matching the ball-handler's position is the ballside or strongside wing. The opposite side is the weakside wing. These designations shift as the ball moves, and most offensive systems are built around them.

Corner and Short Corner

The corner is the area where the sideline meets the baseline — a high-value shooting spot, especially against zone defenses, and also a common trap location for defenses trying to limit ball movement.

The short corner is the area along the baseline halfway between the sideline and the lane line. It's a less obvious offensive position but particularly useful against zones where the short corner sits in a gap between defenders.

Basketball Court Lines by Level — Full Comparison

Line / Marking	NBA	NCAA Men	NCAA Women	FIBA	High School	WNBA
Court Length	94ft	94ft	94ft	91ft 10"	84ft	94ft
Court Width	50ft	50ft	50ft	49ft 3"	50ft	50ft
Key Width	16ft	12ft	12ft	15ft 9"	12ft	16ft
3-Point Line (top)	23ft 9"	20ft 9"	20ft 9"	20ft 6"	19ft 9"	20ft 9"
3-Point Line (corner)	22ft	20ft 9"	20ft 9"	20ft 6"	19ft 9"	20ft 9"
Free Throw Line	15ft	15ft	15ft	15ft 1"	15ft	15ft
Center Circle Dia.	12ft	12ft	12ft	11ft 10"	12ft	12ft
Restricted Area	4ft radius	4ft radius	None	4ft 1"	None	None
Lane Space Marks	2"×6"	2"×6"	2"×6"	Varies	Varies	2"×6"

WNBA and NCAA Women share most NCAA Men dimensions except where noted above.

A Note on Court Surfaces and Line Visibility

On indoor hardwood courts — the standard for NBA, NCAA, and most competitive play — lines are painted directly onto the wood surface and sealed under multiple layers of finish. They stay crisp and visible for years.

Outdoor courts are a different story. Lines painted on asphalt or concrete fade with weathering, and the three-point arc is often the first to become unclear. In recreational settings, players commonly report playing on courts where the restricted area and lane hash marks have worn away entirely, leaving only the key and three-point line visible.

Half-Court Lines

Half-court play uses the mid-court line as a substitute baseline. A standard half-court measures 47ft × 50ft (14.33m × 15.24m) on NBA and college dimensions.

The relevant lines remain: three-point arc, key, free throw line, free throw circle, and center circle (often used as the half-court boundary for inbounds plays). Sideline hash marks, substitution box markings, and mid-court line hash marks are generally absent on dedicated half-court setups.

Conclusion

Basketball court lines fall into four functional groups: boundary lines, scoring lines, lane markings, and secondary markings. Dimensions shift by governing body, but the purpose behind each line stays the same across every level of the game.

Frequently Asked Questions

What is the difference between a baseline and an endline?

They are the same physical line. Baseline refers to the offensive end; endline refers to the defensive end. The name changes based on which team has possession, not the line itself.

What are the small hash marks on a basketball court for?

Hash marks near the free throw lane align non-shooters during free throw attempts. Sideline hash marks serve as reference points for throw-ins and player positioning. Neither type functions as a boundary line.

Does the free throw line extended appear on the court?

No. It is an imaginary coaching reference — no paint, no physical marking. Coaches use it to define zones and establish positioning rules for offense and defense.

Why is the NBA three-point line closer in the corners?

The court width limits the arc geometry near the sidelines. Instead of continuing the curved arc, the line runs straight and parallel 3ft from each sideline, shortening the corner distance to 22ft versus 23ft 9" at the top.

What is the restricted area arc used for?

It prevents defenders from drawing offensive charging fouls by standing directly under the basket. Any contact with a defender inside this arc is ruled a blocking foul, not a charge.