The height of the rim in basketball is exactly 10 feet off the ground. This is the standard for all playing levels from high school and up.
Younger ages play with shorter rims to enable the players to reach the rim with their shots.
The height of the rim is 10 feet because most professional players are six feet and taller. The rim serves as the perfect height to be challenging enough for all players.
Ever since the creation of the sport in 1891 by Dr. James Naismith (the sport was originally called Basket Ball) the height of the rim for professional leagues has always been 10 feet high. That is no different from the NBA, from its first season to now has maintained a 10 foot rim.
The regulation distance for men's Division I in college is the same exact height as an NBA rim, which is 10 feet.
In youth basketball, third and fourth grade players shoot on eight foot rims and fifth grade players shoot on nine foot rims. Sixth grade players and above shoot on 10 foot rims.
The height of an international-sized rim is the same as college and the NBA, 10 feet off the ground. In the Gatorade League or G-League (previously called D-League), the rim measurement is exactly the same as the international, college and the NBA, 10 feet from the floor to the rim.
The backboard is behind the rim and connects the whole apparatus to the ground with a vertical support system while the net is attached to and hangs below the rim. The backboard extends upwards to about 13 feet off the ground.
The net hangs about a foot and a half below the rim (8.5 feet off the ground).