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 — these are the same standards used across all BNSW competitions, from local leagues to state-level programs.
Here’s what your daughter needs based on her age:
| Age | Ball Size | Circumference |
|---|---|---|
| 5–11 | Size 5 | 27.5” (69.5 cm) |
| 12+ | Size 6 | 28.5” (72.5 cm) |
That’s it. If you remember nothing else from this post, just remember: Size 5 for Under 12s, Size 6 from age 12 onwards.
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. She can’t develop proper form because she’s fighting the ball the whole time.
The right size ball sits comfortably in her hands. She can control it. She 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 Dad’s full-size ball (Size 7) and wonders why she can’t dribble properly. We swap it out for the right size and suddenly everything clicks. There’s a reason BNSW made the change — it works.
Size 5 — Under 12s
This is the BNSW standard for all players under 12. It’s noticeably smaller and lighter than what you’d see in an adult game. That’s the point.
At this age she’s still developing hand strength and coordination. A Size 5 lets her actually grip the ball and work on her skills without everything being a struggle. It’s the same ball she’ll use in any BNSW junior competition, so she’ll be training with what she plays with.
Size 6 — Ages 12 and Up
Size 6 is the official women’s game ball and the BNSW standard from Under 14s onwards. It’s what she’ll use through high school, representative basketball, and beyond.
Most girls are ready for this transition around age 12. If she’s 11 and already strong with a Size 5, there’s no rush to move up early. Let her build confidence and technique first — that’s the whole reason BNSW extended the Size 5 to Under 12s.
What About Size 7?
Size 7 is the men’s ball (used in BNSW competitions from Under 16 boys and up). She doesn’t need it. Even if she’s tall for her age. Even if she plays with boys sometimes. For girls, Size 6 is the game ball at every level. It’s the ball that matches the game she’ll play.
Indoor vs Outdoor
This matters more than most parents realise.
- Indoor balls (leather or composite leather) — designed for indoor courts. They feel great but they’ll get chewed up on concrete in about a week.
- Outdoor balls (rubber) — tougher, designed for driveways and outdoor courts. Less grip but they last.
- Indoor/outdoor balls (composite leather) — the middle ground. Work on both surfaces, decent feel, decent durability. This is what I’d recommend for most kids.
If she’s 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 — she should be able to hold it comfortably in one hand (or two for younger girls)
- Properly inflated — a flat ball kills development. Grab a cheap pump if you don’t have one
- Indoor/outdoor composite — unless you know she’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 her dribble in the driveway.
- If she’s 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 her hands, she’s probably ready to size up.
- If she 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 she’s got a ball at home, bring it. We can figure out sizing at the session. I’d rather she 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. She won’t be left out. But if you want to grab her own ball so she can practise at home, now you know what to look for.