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Basketball Size Guide | Mill Sports NZ

Basketball Size Guide | Mill Sports NZ - Shoply

Rajinder Sidhu |

Basketball Size Guide

Basketball is the second most popular sport in the world, with over 450million players all over the world. With over 600 clubs in Australia alone, there’s a good chance you or your children will be interested in getting out onto the court at some point to work out your dribbling, passing, and shooting skills. To make the most out of your training and practice it’s important to have your own ball, and that that ball is the right size for your age, gender, and ability level.

The wrong-sized basketball will lead to bad habits in your technique and it’s impossible to develop to your highest potential when you’re not getting the right grip on the ball. We’ve put together this handy guide on basketball sizes so you can feel confident before making your purchase.


Children’s Basketball Sizes

If your son or daughter is interested in basketball from a very young age, one of these balls will be the perfect place for them to start. 

Toy/Novelty Size Basketball:

The smallest basketball you can buy is the Novelty basketball. These aren’t made with an exact science in mind, with circumferences of balls varying between 9”-20”, and the weights anywhere between 1-5oz. These balls are a great choice for toddlers, or for adults who just want to sink some three-pointers into a novelty-sized net! 

Size 1/Micro-Mini Basketball:

The first official basketball size that will be consistent between manufacturers is the Size 1, or Micro-Mini basketball. These balls weigh in at about 8oz with a circumference of 16”, making them ideal for boys and girls between 2-4 years old who are trying to get an early edge on the competition. 

Size 3/Mini Basketball:

Interestingly, most people skip past the less-popular Size 2 balls, rather opting to transition directly to the Size 3, or Mini basketball. These are the balls that your kids will likely start playing with at school, suiting children between the ages of 4 and 8. The circumference of these balls falls at about 22” while they weigh around 10oz. 

Size 4 Basketball:

For the slightly larger kids around the ages of 5-8, a Size 4 basketball will suit their needs better. These balls weigh in at about 14oz, with circumferences of 25.5”. Consider the size and strength of your younger children when picking between a size 3 or 4 basketball, as an overly heavy or wide ball will make learning proper shooting technique impossible. 

Youth / Women’s Basketball Sizes

Once your child grows out of infancy somewhat, it’s time to transition to a more standard-sized youth ball. Growing their skills and competencies with the smaller balls will give them the foundation they need, while these balls will give them a more realistic feel for the game. 

Size 5 Basketball:

This is considered the standard “youth ball” that’s sold by most sporting goods outlets, being an appropriate size and weight for children between 9-11. The Size 5 ball’s circumference measures at around 27.5”, while the weight jumps up to 17oz. 

Size 6 Basketball:

This is the only ball in the game that doubles as both a youth and adult size basketball. The Size 6 ball is used by male youth teams for players between the ages of 12 and 14, however, it’s also the ball used by women in everything from a high school match to a pro league. Size 6 balls have circumferences of 28.5”, with weights of 20oz. 

Standard Size Basketball

While the WNBA uses Size 6 Basketballs, the standard basketball size for grown men from high school through to professional play is Size 7. 

Size 7 Basketball:

Once boys have truly started to become young men, it’s time to deck them out with a Size 7 Basketball, giving them the truest experience of real, legitimate play. These balls are just 2oz heavier than Size 6, weighing in at 22oz, while their circumference rises by an inch to 29.5”, which may seem like a minor adjustment, but when it comes to the proper technique, weight and gripping ability will make all the difference. 

Basketball Size Chart

By now, you should know everything you need to know about which basketball will suit you or your children best. But to save time if you need a quick refresher, we’ve put together this handy chart, covering everything to do with basketball size by age, weight, and gender. 

Note: cm and gram measurements are approximate roundings.


Size (Title)

Circumference (inches & cm)

Weight (oz & g)



9-20” or 23-51cm

1-5oz or 28-142g

0-4 / Purely for fun

Size 1

16” or 40.5cm

8oz or 227g

2-4 / Learning the absolute basics

Size 3

22” or 56cm

10oz or 283.5g

4-8 / Most people’s first ball

Size 4

25.5” or 65cm

14oz or 397g

5-8 / For slightly bigger kids

Size 5

27.5” or 70cm

17oz or 482g

9-11 / Standard youth ball

Size 6

28.5” or 72cm

20oz or 567g

Boys 12-14 / Women’s pro ball

Size 7

29.5” or 75cm

22oz or 624g

Boys & men 15+ / NBA Ball



Where to Go

Now that you know your NBA basketball size from your youth balls, you need a top supplier to kit you and your family out. Check out Mill Sports NZ for all your basketball needs, with our stock covering various brands and sizes to give everyone the best chance during practice. Check out the full range of basketballs here.

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