Hand a size 5 ball to a group of Under 7s and watch what happens. They will kick it three metres, chase it, kick it again, and by the end of the session half of them are sitting on it. I have seen this exact scenario play out dozens of times across 30 years of coaching Australian youth football, from local clubs through to representative squads. The ball size matters more than most coaches realise, and getting it wrong affects everything from technique development to how much fun kids have on the pitch.

This guide breaks down the correct soccer ball size for every age group in Australia, including FIFA specifications, recommended pressures, and what I have actually found works on the training ground.

What Is the Right Size Soccer Ball for Each Age?

The short answer is three sizes for match and training play, plus two mini sizes for skills work. Here is the complete chart with FIFA specifications:

Ball Size	Age Group (AU)	Circumference	Weight	Recommended PSI
Size 1	All ages (skills only)	45-50 cm	Varies	3-6 PSI
Size 2	3-5 years (skills)	55-56 cm	Varies	3-6 PSI
Size 3	Under 6 – Under 9	58-61 cm	310-340g	8.5 PSI
Size 4	Under 10 – Under 13	63.5-66 cm	350-390g	8.5-9 PSI
Size 5	13+ / Senior	68-70 cm	410-450g	9-10 PSI

These are FIFA guidelines that Football Australia follows. The PSI ranges above are my recommended training pressures, they sit at the lower end of the official FIFA range (8.5-15.5 PSI) because slightly softer balls are better for technique development in younger age groups.

Understanding Size 3, 4, and 5

Size 3, The Junior Ball

Size 3 is the standard for the youngest age groups in Australian football. If you are coaching MiniRoos (Under 6 through Under 9), this is your ball. It is smaller, lighter, and proportionate to smaller bodies. Kids can actually control it, head it without fear, and develop real touch.

In my experience coaching junior representative squads, the biggest mistake clubs make is letting U8s train with whatever balls are in the shed, which usually means a mix of deflated size 4s and rock-hard size 5s. Standardise on size 3 for these age groups. It changes everything.

As Horst Wein outlines in Developing Youth Soccer Players, young athletes need equipment that matches their physical development. A size 5 ball for a six-year-old is the equivalent of asking an adult to train with a medicine ball, the proportions are all wrong.

Circumference: 58-61 cm  |  Weight: 310-340g  |  Recommended PSI: 8.5 PSI for training

---

Size 4, The Transition Ball

Size 4 covers the U10 through U13 bracket in most Australian states. This is the age where players start developing real technique, first touch, passing weight, striking accuracy, and the ball size supports that progression.

One thing I have noticed at representative level is that the jump from size 3 to size 4 between U9 and U10 catches some kids off guard. Their passing suddenly feels off, they are mis-timing headers, and shooting feels heavy. If you are coaching an U10 team at the start of the season, give them a few sessions to adjust rather than assuming something is wrong with their development. It is the ball, not the player.

Circumference: 63.5-66 cm  |  Weight: 350-390g  |  Recommended PSI: 8.5-9 PSI for training

---

Size 5, The Full Size Ball

Size 5 is the standard from Under 13 upward through to senior and professional football. This is the ball most coaches are familiar with. FIFA match balls are always size 5, and it is what your players will use from this age onward.

Circumference: 68-70 cm  |  Weight: 410-450g  |  Recommended PSI: 9-10 PSI for training, up to 15.5 PSI for official matches

Australian Age Groups, MiniRoos to Senior

This is where it gets specific to coaching in Australia, and where I see the most confusion. Football Australia runs the MiniRoos program for the youngest age groups, and each state federation has slightly different age brackets for competitions. Here is the general structure:

Program / Level	Age Group	Ball Size
MiniRoos (Small-Sided)	Under 6 – Under 9	Size 3
MiniRoos (Transitional)	Under 10 – Under 11	Size 4
Junior Competition	Under 12 – Under 13	Size 4
Youth Competition	Under 14 – Under 18	Size 5
Senior / NPL / State League	18+	Size 5

Important: Check your state federation’s specific regulations. In some states, the U9 to U10 transition happens mid-year. In others, it aligns with the calendar year. Your club registrar should have the current season’s ball size requirements.

The MiniRoos program specifically mandates smaller balls and smaller pitches to keep the game proportionate to the players. This is not just a guideline, it is backed by development research showing that kids learn faster when the environment matches their physical capacity. Learn about game lengths for each age group →

What About Futsal Balls?

Futsal uses its own ball sizing, and this trips up coaches who run both outdoor and indoor programs. Futsal balls are heavier for their size (they have a reduced bounce) and should never be substituted with outdoor balls.

Futsal Size	Age Group	Circumference	Recommended PSI
Futsal Size 3 (Junior)	Under 10 / Girls Under 12	58-60 cm	8-10 PSI
Futsal Size 4 (Senior)	10+	62-64 cm	9-10 PSI

If you are coaching both outdoor and futsal, keep separate ball bags. Mixing them up leads to sessions where half the balls are bouncing differently and players cannot develop consistent touch.

For younger kids who aren’t ready for futsal’s touch demands, hover soccer balls are a third indoor category worth knowing about – foam-bumpered, low-velocity, sized for ages 3 to 12 and built for hardwood or carpet play. See the hover soccer ball roundup for the picks I recommend.

How to Properly Inflate Your Soccer Ball

Getting the right ball is only half the equation. Inflation technique and correct pressure are just as important.

Step 1: Lubricate the needle with glycerin or silicone before insertion. A dry needle damages the valve over time.

Step 2: Insert the needle straight into the valve, never at an angle.

Step 3: Inflate to the recommended PSI for the ball size (see the chart above). Use a pressure gauge, not the squeeze test.

Step 4: Remove the needle straight out, same angle you went in.

The single biggest mistake I see in junior coaching is over-inflation. A size 3 ball pumped to 12 PSI is a rock. Kids flinch when it comes at them, they cannot control it, and headers become something to avoid rather than develop. Keep junior balls at the lower end of the PSI range, around 8.5 PSI for training, and watch the difference it makes to confidence and technique.

What I Have Learned About Ball Selection After 30 Years

Buy training balls, not match balls, for sessions. Match balls are designed for performance on match day. Training balls are designed to survive being belted into fences 200 times a week. I have seen clubs spend their entire equipment budget on top-tier match balls and then wonder why they are replacing them every two months.

Check pressure weekly, not seasonally. Temperature changes affect pressure. A ball inflated in summer will be noticeably softer in winter. Get into the habit of checking every Monday and topping up as needed.

Let the kids feel the difference. At the start of a season, I will sometimes bring a size 3, 4, and 5 to a junior session and let the players handle all three. It helps them understand why we use specific sizes and builds their awareness of the equipment they are working with.

Frequently Asked Questions

What size soccer ball does a 7-year-old use?

A size 3. In Australia, MiniRoos programs for Under 6 through Under 9 use size 3 balls exclusively. The smaller size and lighter weight are proportionate to younger players, making it easier to develop proper technique and ball control. Check with your local club to confirm your state’s specific age brackets. For specific brand picks across all sizes, see our best soccer balls Australia roundup.

What is the difference between a size 4 and size 5 soccer ball?

Size 4 is approximately 5 cm smaller in circumference and 50-60g lighter than a size 5. For players, the difference is noticeable in passing weight, shooting power, and heading. Size 4 is used for U10 to U13, while size 5 is the full adult size used from U14 onward and in professional football worldwide.

Can I use a futsal ball for outdoor training?

You can, but I would not recommend it for regular sessions. Futsal balls have a reduced bounce and different weight distribution compared to outdoor balls. Using one occasionally for close-control drills on grass can be a useful variation, but for standard outdoor training, stick with the correct outdoor ball for the age group. See our full coaching equipment guide →

How do I know if my soccer ball is the right pressure?

Use a pressure gauge, they cost around $10-20 and clip onto your coaching bag. The recommended PSI is usually printed near the valve on the ball. If you cannot find it, aim for 8.5 PSI for size 3 and 4 training balls, and 9-10 PSI for size 5. If you can press your thumb in and create a visible dent, it is under-inflated. If it feels like a rock and bounces excessively, it is over-inflated. For the full guide to choosing soccer balls by age and surface, see our complete soccer balls guide. See the full ball pressure PSI guide →