Basketball Hoop Rim Diameter vs Ball Size (Comparison)

It might be your first time in front of a basketball hoop. As you look at the ball in your hand, you start wondering, what is the basketball hoop rim diameter? Also, can the ball you’re holding fit and go through the rim?

The standard basketball rim used by NBA professionals, university, and senior high players has an 18-inch inside diameter and a radius of 9 inches. It can fit 1 NBA-sized ball with a 29.5 inches circumference. 

Understanding the size of the basketball hoop or rim can help you choose the right model for your desired setup, particularly if you’re building a basketball play area at home. Keep reading to know more about the sizes of basketballs and hoops.

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basketball hoop rim

Relatively all basketball hoop rim diameters are the same, regardless of level. In other words, the basketball hoop used in high schools, colleges, and official NBA courts have the same hoop rim diameter of 18 inches.

The only exceptions to this rule are unique basketball systems. Portable basketball hoops, hoops for children, and wall-mounted indoor basketball hoops may have variations to their rim sizes.

What is the Circumference and Diameter of a Basketball?

The NBA has specified basketball sizes for men’s, women’s, and junior league games, and also unofficial games for children and youth. These NBA size specifications are the guidelines to help you choose the right ball for yourself or your children.

The official size of the basketball used by the NBA is 29.5 inches in circumference with an average diameter of 9.51 inches. With those dimensions, the ball can go through a standard rim with an inner clearance diameter of 18 inches. That’s the same size used throughout men’s college and high school basketball leagues. The WNBA uses a slightly smaller ball, measuring 28.5 inches in circumference. Women use this ball from 9-years-old and up.

Boys in middle school (ages 12 and up) use a 29.5-inch ball. For anyone, male or female, between the ages of nine and 11, a ball size of 28.5 inches in circumference is recommended. Boys and girls between the ages of 4 and 8 should use a basketball between the sizes of 22 inches and 25.5 inches in circumference.

NBA basketball is inflated to a pressure of 7.5 to 8.5 PSI and the WNBA uses the same regulations. The NCAA, inflation requirements are given in weight instead of PSI, with the men’s ball having a maximum weight of 22 ounces and the women’s ball having a maximum weight of 20 ounces.

What is the Height of a Basketball Rim?

Basketball rim height

The proper rim heights will not only make it easier for players to score a basket, it will also assist in their basketball development. No matter how tall a rim is, players should still show proper shooting form to make a basket.

When a younger child uses a 10-foot rim, their shooting form is likely to unravel since the child is simply throwing the basketball as hard as he or she can. This is similar to a half-court an adult might attempt. It’s fun to try, but your shooting mechanics go out the window. Also, seeing the ball go through the hoop, which is much more likely to happen on a shorter rim, adds confidence and makes the game more fun for any players.

The recommended heights for basketball goals are the same for both male and female. For professional basketball all the way down to 6th grade the goal is 10-feet. For 5th grade, the goal should be placed at 9-feet. And for the 3rd and 4th grade(8 to 10 years-old) 8-foot rims. Lastly 6-foot rims for kindergarten, 1st, and 2nd grades.

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How many balls can fit in a basketball rim?

The size of the basketball rim’s radius is 9 inches and the diameter is 18 inches. The circumference of the rim is 56.5 inches. The rim itself is made of tensile carbon steel and made of around 5/8″ in diameter of solid steel rod.

A men’s basketball diameter is around 9.5 inches and circumference is 29.5 inches. Not all men’s basketballs are made equal and not all basketballs are filled with the right amount of PSI or air.

Two men’s basketballs fit in a basketball hoop but will not go through. Technically two and a half men’s balls fit in the hoop. Some will argue that they will go through but either they are pushing one ball through before the other just a touch. Or the balls are not official size and are not properly inflated.

A women’s basketball diameter is around 9 inches and circumference is 28.5 inches. Its diameter is half an inch shorter when compared to a men’s ball and a full inch smaller in circumference also.

Two women’s ball’s fit through a basketball rim at the same time within a quarter of an inch to spare. Three women’s basketballs can sit on top of the rim but would not pass through.

How much weight can a basketball rim hold?


This is going to depend on several factors mostly on how the rim is supported and what the rim is made of. Most rims are made of steel but are still bendable especially if they are not spring loaded or if it’s a thick steel rim.

Adjustable rims

These rims generally are mass produced; you can find one on sale from $150 and up. Although it’s less expensive and some might be tempted to purchase it, we suggest looking at the quality of the rim over price. Usually, hanging on some adjustable rims although it’s steel, you can potentially break or pull the whole rim down including the base and pole, even though it is filled with water or sand.

Spring loaded rims

Like adjustable rims, these rims are built of high-grade steel and have a spring on them for better dunking experience. However, although they are bendable in nature they can still potentially break if you dunk on them several times. Usually, these rims cost $700 and up. Good quality, often cost-effective.

Double rims

Double rims are made of high-grade steel and are very thick. These rims are durable and usually attached to a strong structure.

Double rims actually can be a big help to basketball players trying to practice their shooting skills. Unlike other basketball hoops, double rims force players to make shots through the center every time. There is no room for error when shooting on double rims.

Definitely stronger and better than a single rim. This is perfect for outdoor plays.

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Basketball rim size and ball related questions


How high do you need to jump to dunk?

You’ll need to jump roughly 24 inches to touch the rim and 30 inches to dunk a full sized basketball (assuming average arm length). While the height difference between a 5 foot 9 person and a 6 foot person is only 3 inches, it’s actually a lot easier around this height.

Are NBA rims different from college?

NBA rims are made of a leather couch. In the NCAA, they use a tin can material.

What is a size 7 basketball?

Size 7 (29.5″) is the official size of all adult basketballs, suitable for males aged 13 years and over. The NBA Official Game Ball is a size 7 basketball and meets all size and weight specifications set by the NBA with a circumference of 29.5″ (75cm).

How tall is a high school basketball hoop?

For junior high, high school, NCAA, WNBA, NBA and FIBA, the rim is exactly 10 feet off the ground. Rims at every level of play are 18 inches in diameter. Backboards are also the same size at each of these levels. A regulation backboard measures 6 feet wide and 42 inches (3.5 feet) tall.

For more basketball hoop and ball related questions answered, check out the video below:

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