Basketball court dimensions in practice vary in overall length and width. In many areas of the country, older high school gymnasiums in particular have smaller overall size than regulation. Many of these same gyms have varying backboard designs and measurements.
Even though Pro, College, High School and Junior High School courts differ in overall size and layout, the interior markings for the “Foul Line” and “The Backboard and Rim” are the same.
Overall Court Regulation Sizes are typically
NBA Professional and College – 94 feet long and 50 feet wide
High School – 84 feet long and 50 feet wide
Junior High – 74 feet long and 42 feet wide
The Foul Line
For all courts the “foul line” distance is 15 feet from the foul line to the front of the backboard. This measurement is commonly confused as from the center of the basket and front of the rim.
The Key (the Lane):
The Key (also called the Lane) is different for Professional (NBA) and College/High School.
Professional (NBA): The key is 16 feet wide
College (NCAA) and High School: The key is 12 feet wide
Regulation courts have the backboard extending out 4 feet over the baseline into the key. A 6 foot arc (half circle) extends from the foul line away from the basket to complete the key.
The 3 Point Line (Arc)
Three Point lines differ as follows:
NBA Basketball Courts – the 3 point arc is 22 feet to the center of the rim on the sides with a straight line extending out 16 feet 9 inches from the baseline. Past those points the line extends out 23 feet 9 inches from the center of the rim.
Mens and Womens College Basketball Courts – the 3 point arc is 20 feet 9 inches.
High School Basketball Courts – the 3 point arc is 19 feet 9 inches.
The Backboard and Rim
The regulation distance from the ground to the top of the rim is 10 feet for all levels of play. Regulation backboards are 6 feet wide (72 inches) by 42 inches tall. All basketball rims (hoops) are 18 inches in diameter. The inner square on the backboard is 24 inches wide by 18 inches tall.
All line markings on the floor are 2 inches wide and can vary in color.
The Restricted Arc
The restricted area arc is a semi-circular arc drawn around the area directly underneath the basket. Defensive players whose feet are inside this arc cannot draw charging fouls. The restricted arc in NBA and WNBA competition is a radius of 4 feet (1.22 m) from the center of the basket. In NCAA courts (both men's and women's) the arc is a radius of 3 feet (0.91 m) from the center of the basket