Basketball Hoop Dimensions: Rim Height, Diameter and Backboard Size
Exact rim, backboard and net measurements for regulation hoops, the right height for each age group, and how home hoops compare.
A regulation basketball hoop has its rim 10 ft (3.05 m) above the floor, with an inside diameter of 18 in (45.7 cm). The rim hangs from a 72 × 42 in (183 × 107 cm) backboard, with its inner edge 6 in (15 cm) from the board. The same rim height applies in the NBA, college, high school and FIBA play.
- Rim height
- 10 ft (3.05 m)
- Rim diameter
- 18 in (45.7 cm)
- Backboard
- 72 × 42 in
- Top of backboard
- about 13 ft
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Regulation basketball hoop dimensions
The NBA, WNBA, NCAA, US high schools and FIBA all use the same hoop. The only real difference is that FIBA defines it in metric units, which round to almost the same figures.
| Part | US rules (NBA, NCAA, NFHS) | FIBA |
|---|---|---|
| Rim height (floor to top of rim) | 10 ft (3.05 m) | 3.05 m |
| Rim inside diameter | 18 in (45.7 cm) | 450–459 mm |
| Rim rod thickness | about ⅝ in | 16–20 mm |
| Rim inner edge to backboard | 6 in (15 cm) | 151 mm |
| Backboard (width × height) | 72 × 42 in (183 × 107 cm) | 1.80 × 1.05 m |
| Inner rectangle (shooter's square) | 24 × 18 in (61 × 46 cm) | 59 × 45 cm |
| Bottom edge of backboard | about 9 ft 6 in | 2.90 m |
| Backboard face from baseline | 4 ft (1.22 m) | 1.20 m |
| Net length | 15–18 in | 40–45 cm |
The top of the rim is level with the bottom line of the inner rectangle, which sits about 6 in (15 cm) above the bottom edge of the board. So the rectangle runs from 10 ft to 11 ft 6 in, and the top of a regulation backboard is about 13 ft (3.95 m) above the floor.
How big is a basketball hoop compared with the ball
An 18 in rim is almost twice the diameter of a men's ball. A size 7 ball has a 29.5 in circumference, which is a 9.4 in (23.9 cm) diameter, leaving about 8.6 in to spare across the hoop. A women's size 6 ball (28.5 in, 9.1 in across) has slightly more.
The rim's radius is 9 in, so the center of the basket is 15 in (38 cm) in front of the backboard face, and 5 ft 3 in from the baseline. Every court line is measured from that point; the basketball court dimensions guide lists them by league.
Basketball hoop height by age
A lower rim lets young players shoot with a proper one-hand form instead of pushing the ball from the chest. USA Basketball and the Jr. NBA program recommend 8 ft for ages 7 and 8, 9 ft for ages 9 to 11 and 10 ft from age 12. There is no official height for younger children; 6 to 8 ft is the usual range. Leagues set their own rules, so check before you set a home hoop to match a team.
| Age | Rim height | Metric | Typical ball |
|---|---|---|---|
| Under 7 | 6–8 ft | 1.83–2.44 m | Size 3 or 4 |
| 7–8 | 8 ft | 2.44 m | Size 4 or 5 |
| 9–11 | 9 ft | 2.74 m | Size 5 or 6 |
| FIBA mini-basketball (under 12) | 8 ft 6 in | 2.60 m | Size 5 |
| 12 and over | 10 ft | 3.05 m | Size 6 (girls, women), size 7 (boys, men) |
Ball circumferences: size 7 is 29.5 in (75 cm), size 6 is 28.5 in (72 cm), size 5 is 27.5 in (70 cm), size 4 is 25.5 in (65 cm) and size 3 is 22 in (56 cm). Youth ball recommendations differ between programs by one size, so the column above shows the common choice.
Most adjustable home systems range from 7 or 7½ ft to 10 ft. If you buy for a child under 7, check the lowest setting: many hoops sold as "adjustable" stop at 7½ ft, which is still high for a 5-year-old.
Home basketball hoop sizes
Home hoops use the same 18 in rim and 10 ft height but smaller backboards. The board width is the size printed on the box.
| Backboard width | Metric | Usual setup | Notes |
|---|---|---|---|
| 44 in | 112 cm | Portable | Entry-level; bank shots feel cramped |
| 48–50 in | 122–127 cm | Portable, roof mount | Common driveway size |
| 54 in | 137 cm | Portable or in-ground | Common mid-range size |
| 60 in | 152 cm | In-ground | Close to the feel of a gym board |
| 72 in | 183 cm | In-ground, wall mount | Regulation width |
- Backboard material: tempered glass gives the truest rebound and is used on regulation boards. Acrylic is lighter and cheaper but softer. Polycarbonate is nearly unbreakable and common on portable hoops.
- Pole size: residential in-ground poles are usually 4 to 6 in square steel. Larger poles flex and shake less after dunks and hard rebounds.
- Overhang (extension): the horizontal distance from the front of the pole to the backboard face. Regulation is 4 ft. Home systems range from about 2 to 6 ft; aim for 3 ft or more so players driving to the basket do not run into the pole.
Space you need for a hoop
- Height clearance: the top of a 42 in board at 10 ft is 13 ft up. A wall-mounted or roof-mounted hoop needs that much clear height above the playing surface, plus room for the ball to arc.
- Playing depth: the free-throw line is 15 ft from the backboard. Allow at least 20 ft of flat surface in front of the board to practice free throws and short jumpers, and 25 ft or more for a high school three-point line.
- Portable bases: the base sits behind the backboard and is filled with water or sand. A 35-gallon base holds about 290 lb of water; sand weighs roughly half again as much for the same volume and resists tipping better.
- Garage door clearance: a roof or garage-mounted hoop must sit above the door opening. Standard residential doors are 7 or 8 ft tall; the garage door size guide lists the openings.
Home rims are not built for dunks unless the box says breakaway rim and the system is in-ground. Hanging on a portable hoop's rim is the main cause of tip-overs. Keep the base filled to the manufacturer's level.
How to check your hoop height
- Measure to the top of the rim, not to the bottom or to the net hooks. Hook a tape on the front of the rim and drop it to the playing surface.
- Measure at the front of the rim, the edge farthest from the backboard. Rims on worn systems can droop by ½ in or more.
- Measure on the playing surface, not the grass beside a driveway. A sloped driveway can put the rim 3 to 6 in off from where the shooter stands.
- Compare with the target: 120 in (305 cm) for regulation, 108 in for 9 ft, 96 in for 8 ft.
For the full layout of a home or school court, see the basketball court size guide. Other backyard equipment sizes are in the swing set dimensions guide and the trampoline size chart, and the sports sizes hub covers courts and goals for every major sport.
Frequently asked questions
How tall is a basketball hoop in cm?
A regulation hoop is 305 cm (3.05 m) from the floor to the top of the rim. FIBA mini-basketball for under-12s lowers it to 260 cm (8 ft 6 in).
Are NBA hoops bigger than high school hoops?
No. NBA, WNBA, college, high school and FIBA hoops all use an 18 in (45.7 cm) rim at 10 ft (3.05 m), on a 72 × 42 in or 1.80 × 1.05 m backboard. Only the court markings change between levels.
How high is the top of a basketball backboard?
On a regulation hoop, the bottom of the backboard is about 9 ft 6 in (2.90 m) above the floor and the top is about 13 ft (3.95 m). That is the clearance a gym ceiling or garage roofline must exceed.
What does a 9-ft rim look like next to a 10-ft rim?
The rim is the same 18 in hoop, only 12 in lower. Shots need a noticeably flatter arc, which is why 9 ft is recommended for ages 9 to 11: it lets them shoot with proper form instead of heaving the ball.
What is the basketball hoop height in Europe, Japan or Malaysia?
The same 3.05 m (10 ft). FIBA rules apply in Europe and Asia, and FIBA uses the same rim height and 450 mm rim as the NBA. Youth mini-basketball under FIBA uses 2.60 m.
How big is a mini basketball hoop?
There is no standard. Over-the-door hoops usually have a backboard around 18 × 12 in to 24 × 16 in and a rim about 9 to 10 in across, sized for a 5 to 7 in foam or rubber ball. Measure the door opening and the clearance above it before buying.