What Size Basketball Should I Get My Kid?

The Quick Answer

Basketball sizes go by number. The smaller the number, the smaller the ball. We follow the Basketball NSW (BNSW) guidelines which are used across all BNSW competitions, from local leagues to state-level programs.

Here’s what your child needs based on their age:

Age	Boys	Girls
5–11	Size 5	Size 5
12–13	Size 6	Size 6
14–15	Size 6	Size 6
16+	Size 7	Size 6

The simple version: Size 5 for Under 12s. Size 6 from age 12. Boys move to Size 7 from age 16.

In 2023, Basketball NSW officially introduced the Size 5 ball for all Under 12 competitions, including the Spalding Waratah League, Skills Days and High Performance programs. The change came after research with other states (Basketball Victoria made the same move in 2022) showing that a correctly sized ball helps younger players develop better shooting and ball handling technique.

As BNSW’s General Manager of Coaching & Development Brett Coxsedge put it: “The introduction of the size 5 ball will allow a focus on better shooting and ball handling skills for our junior players. This will allow younger players and beginners to hone and perfect their skills at an early age.”

Why Size Matters

A ball that’s too big or too heavy makes everything harder. Dribbling feels awkward. Shooting means heaving it at the ring. They can’t develop proper form because they’re fighting the ball the whole time.

The right size ball sits comfortably in their hands. They can control it. They can shoot with proper technique instead of just launching it. That’s where real skill development happens.

I see it all the time. A kid shows up with a full-size ball (Size 7) and wonders why they can’t dribble properly. We swap it out for the right size and suddenly everything clicks. There’s a reason BNSW made the change.

Size 5 — Under 12s

This is the BNSW standard for all players under 12, boys and girls. It’s noticeably smaller and lighter than what you’d see in an adult game. That’s the point.

At this age kids are still developing hand strength and coordination. A Size 5 lets them actually grip the ball and work on their skills without everything being a struggle. It’s the same ball they’ll use in any BNSW junior competition, so they’ll be training with what they play with.

Size 6 — Ages 12 and Up

Size 6 is the official women’s game ball and the BNSW standard for girls from Under 14s onwards. For boys, Size 6 is used from Under 14s through to Under 16s before they move up to Size 7.

Most kids are ready for this transition around age 12. If your child is 11 and already strong with a Size 5, there’s no rush to move up early. Let them build confidence and technique first. That’s the whole reason BNSW extended the Size 5 to Under 12s.

Size 7 — Boys 16 and Up

Size 7 is the men’s game ball, used in BNSW competitions from Under 16 boys onwards. It’s the ball boys will use through senior competitions and representative basketball.

For girls, Size 6 is the game ball at every level from Under 14s up. Even if she’s tall for her age or plays in mixed competitions, Size 6 is the standard.

Indoor vs Outdoor

This matters more than most parents realise.

Indoor balls (leather or composite leather) are designed for indoor courts. They feel great but they’ll get chewed up on concrete in about a week.
Outdoor balls (rubber) are tougher, designed for driveways and outdoor courts. Less grip but they last.
Indoor/outdoor balls (composite leather) are the middle ground. Work on both surfaces, decent feel, decent durability. This is what I’d recommend for most kids.

If your child is mostly practising in the driveway and coming to one or two indoor sessions a week, an indoor/outdoor composite ball is the go. Spalding’s TF-Grind is a solid option. It’s actually the ball BNSW stocks for their programs.

What to Look For When Buying

You don’t need to spend a fortune. Here’s what matters:

Right size — Size 5 for Under 12s, Size 6 from age 12 (follow the BNSW standard)
Decent grip — they should be able to hold it comfortably in one hand (or two for younger kids)
Properly inflated — a flat ball kills development. Grab a cheap pump if you don’t have one
Indoor/outdoor composite — unless you know they’ll only play on one surface

You can find a solid ball for $25–$50. Spalding, Molten and Wilson all make good ones in the right sizes.

The Driveway Test

Not sure if the ball is right? Watch them dribble in the driveway.

If they’re slapping at it and can barely keep it going, the ball might be too big or too heavy.
If it looks like a tennis ball in their hands, they’re probably ready to size up.
If they can dribble comfortably at waist height with some control, that’s the right fit.

Bring Whatever You’ve Got

Here’s the thing. Don’t let the ball stop you from getting started. If your child has a ball at home, bring it. We can figure out sizing at the session. I’d rather they show up with the wrong ball than not show up at all because you weren’t sure what to buy.

At Inner Game, we’ve always got spare balls at every session. No one gets left out. But if you want to grab them their own ball so they can practise at home, now you know what to look for.

Want to put that new ball to use? Have a look at our weekly Skills Classes, private 1-on-1 coaching or school holiday camps, or book a free trial and bring the ball along.