Using NBA rules as the reference, the rim opening is 18 inches across internally, and the rim's upper edge is 10 feet above the floor. The backboard is 72 inches wide by 42 inches high.
“Hoop size” can refer to several different measurements. Specify whether you mean the ring opening, its height, the backboard, or the net. A product described by its backboard width is not describing the rim's diameter.
The measurements below come from NBA Rule 1, Section II. Metric equivalents are calculated.
| Part or measurement | NBA specification | Metric equivalent |
|---|---|---|
| Rim opening, inside diameter | 18 in | 45.72 cm |
| Floor to upper edge of rim | 10 ft / 120 in | 3.048 m |
| Backboard, width × height | 72 × 42 in | 182.88 × 106.68 cm |
| Net length | 18 in | 45.72 cm |
These are NBA specifications, not a claim that every recreational product or every governing body uses identical equipment rules.
Read each row as a separate dimension. A backboard can be much wider than the ring attached to it, while the height above the playing surface is another measurement altogether.
Inside diameter runs through the center from one inner edge of the ring to the opposite inner edge. It excludes the thickness of the metal. Measuring outside edge to outside edge would include that thickness and give a larger value.
RIM: TOP VIEW
.--------.
.-' '-.
|<--- 18 in ---->|
'-. .-'
'--------'
inside opening
Labeled schematic, not a scale drawing.
For the NBA height measurement, use the floor and the upper edge of the ring as the two reference points. The hanging net, the bottom of the metal, and the top of the backboard are different endpoints.
A slanted line to the ring is not the vertical distance. When checking a measurement, keep the reference points and direction consistent. For an adjustable system, the selected setting also matters.
Backboard dimensions describe a rectangle: horizontal width first, vertical height second. They do not tell you how high the entire assembly has been mounted.
The net-length figure in the NBA table describes the hanging net itself. It is not the height of the basket above the court. When someone asks for “basketball net height,” clarify which of these two measurements they want.
Replacement parts also need more than a matching measurement. Compare the manufacturer's attachment and compatibility information for your specific system; a matching nominal size does not establish that a part fits.
The NBA and USA Basketball youth guidelines give age-specific recommendations:
| Age group | Recommended basket height | Metric equivalent |
|---|---|---|
| Ages 7–8 | 8 ft | 2.4384 m |
| Ages 9–11 | 9 ft | 2.7432 m |
| Ages 12–14 | 10 ft | 3.048 m |
The linked age-group documents are recommendations for competition organizers. They allow for practical limitations, including facilities where the basket cannot be adjusted.
A 10-year-old falls within the 9–11 age band, for which the guideline recommends a 9-foot basket. However, the label “10U” does not by itself establish the rim height used by a particular league or tournament. Check that event's equipment rules.
For ages 7–8, the guideline recommends 8 feet. Confirm the actual age band and the local rule rather than assuming every 8U program follows the same setting.
A youth recommendation and the NBA regulation measurement answer different questions. Use the competition's applicable rules when checking an organized game.
Before comparing a specification or a measured value, identify four things:
For metric comparisons, use 1 inch = 2.54 centimeters and 1 foot = 0.3048 meters, as defined in NIST's conversion tables.
This guide explains measurements. It is not a mounting plan: the equipment manufacturer's instructions determine how a particular system is assembled, supported, or adjusted.
No. The rim opening is a circular measurement, while the backboard has a rectangular width and height. A listing's prominent size number may refer to the backboard.
The specified rim height is 120 inches, equivalent to 10 feet. Measure to the upper edge of the ring.
No. Net length and rim height are separate dimensions. A longer or shorter hanging net does not change the ring's height above the playing surface.
No universal height follows from the age label alone. Nine feet is the NBA/USA Basketball recommendation for ages 9–11; the league or tournament can specify its own equipment setting.
Not necessarily. Treat the backboard and rim specifications separately, and check the stated inside diameter of the ring.
Specifications checked October 31, 2026. NBA measurements and youth recommendations are labeled separately; this page does not establish the rules of an individual school, league, or tournament.