- 1. How Australian Baby Clothing Sizes Work
- 2. Australian Baby Clothes Size Chart
- 3. Size 000: The Right Starting Point for Most Newborns
- 4. What to Dress Your Baby in at Size 000
- 5. Buying Size 000 as a Baby Gift
- 6. Signs It’s Time to Move Up from Size 000
- 7. Frequently Asked Questions
- 8. Using the Right Size Makes the First Weeks Easier
You are holding two baby outfits — one labelled 000, one labelled 0000 — and you have no idea which one your baby will actually wear first. The Australian sizing system does not match international labels, and different brands often size quite differently.
This guide walks you through the full Australian baby clothes sizing system, from 0000 through to toddler sizes. It also takes a closer look at size 000 — the starting point for most newborn wardrobes — including how long it fits, what babies typically wear in it, and why it is often the safest size to buy as a gift. This guide covers:
• How the Australian number-based sizing system works
• A complete size chart from 0000 to size 3
• Why size 000 is the practical default for most newborns
• What to dress your baby in at size 000, by daily scenario
• How to choose size 000 as a baby gift
• The signs that it is time to move up from 000
• Five frequently asked questions on Australian baby sizing
• Use the right size to make the first weeks easier
How Australian Baby Clothing Sizes Work
Australian baby clothing uses a number-based system: 0000, 000, 00, 0, 1, 2, 3. These numbers do not directly correspond to the month-based labels you see on international brands (NB, 0–3M, 3–6M), which is one of the first things that catches new parents off guard.
The most important thing to understand: Australian baby clothes sizes are based on weight and body length, not age. Age ranges are only a rough guide — two babies born in the same week may still wear different sizes. Use your baby's weight and length — not their birth date — as your guide.
Why Australian Baby Sizes Feel Confusing to New Parents
One reason Australian baby sizing feels confusing is that the numbers get smaller before they get larger. New parents often assume 0000 is bigger than 000, when in reality it is the smallest standard newborn size. It also gets confusing when brands mix Australian sizing with month-based labels like NB or 0–3M on the same website
Australian Baby Clothes Size Chart
The table below covers the full AU size range. Weight is the most reliable guide from birth to around 12 months; height becomes more useful after that as growth patterns become more individual.
| AU Size | Approx Age | Weight Guide | Height Guide | International Equiv |
| 0000 | Birth–4 weeks | Up to 4 kg | Up to 56 cm | Preemie / NB (small) |
| 000 | 0–3 months | 3–6 kg | 57–62 cm | NB / 0–3M |
| 00 | 3–6 months | 6–8 kg | 63–68 cm | 3–6M |
| 0 | 6–12 months | 8–10 kg | 69–76 cm | 6–12M |
| 1 | 12–18 months | 10–12 kg | 77–84 cm | 12–18M |
| 2 | 18–24 months | 12–14 kg | 85–92 cm | 18–24M |
| 3 | 2–3 years | 14–16 kg | 93–100 cm | 2T / 3T |
Most parents preparing their first wardrobe find that size 000 is where they actually begin. The sections below focus on this size in detail.
Size 000: The Right Starting Point for Most Newborns
Size 000 is designed for babies weighing 3–6 kg and measuring 57–62 cm in body length. According to the Australian Institute of Health and Welfare, the average birth weight in Australia is around 3.3 kg — which means most healthy newborns fall within the 000 weight range from birth, and grow into the full range over the first few weeks.
Why 000 is the practical default
Size 0000 is generally intended for smaller newborns or babies born early. For a typical birth-weight baby (3.2–3.8 kg), there is often no meaningful window where 0000 fits, but 000 does not. Many parents who stock up on 0000 find their baby outgrows it before they have worn most pieces.
Size 000, on the other hand, covers a wider window: the average baby stays in 000 for around six to ten weeks, depending on how quickly they are growing. For many parents, 000 ends up being the size they use more than any other in the newborn stage. That longer wear window is why most starter wardrobes are built around it.
How many to buy
For a working rotation that covers daily changes without washing every day:
• Bodysuits: 8–10 pieces (plan for two to three changes a day in the early weeks)
• Growsuits: 4–6 pieces (used daily for sleep and cooler conditions)
• Rompers or outer layers: 2–3 pieces (useful but not the priority)
What to Dress Your Baby in at Size 000
Most babies spend their size 000 stage doing three things repeatedly: sleeping, being at home, and heading out with their parents. Here is how to approach each one.
At home
Frequent changes are the reality of the first weeks — spit-up, nappy leaks, and temperature shifts mean two to three outfit swaps a day is normal. A bodysuit handles this well: it fastens at the crotch, stays in place through the day, and comes off quickly without a full undressing. Choose sleeve length based on room temperature — short-sleeve in warmer conditions, long-sleeve when the house is cooler. Beyond that, keep it simple.
Out and about
The hardest part of dressing a newborn outside the home is not temperature — it is unpredictability. You can leave in the morning with one plan and end up in three completely different environments: a warm car, a cold supermarket, and an overly air-conditioned café. Because of this, the most practical approach is to think in layers, not outfits. A simple base layer (like a bodysuit or growsuit) does most of the work. Over that, choose something you can remove in one step without fully undressing the baby — a light growsuit, cardigan, or wrap-style layer. A muslin cloth in the nappy bag also helps more than people expect — not as clothing, but as a quick temperature buffer when conditions change unexpectedly.
Sleep
A fitted long-sleeve growsuit is the standard choice for sleep at this size. For most Australian conditions in the 16–22°C range, a growsuit paired with an appropriate TOG sleeping bag handles overnight temperature changes without needing adjustment. Avoid using a hat during sleep — even in cooler rooms, babies can overheat more easily when extra head covering traps body heat.
These three scenarios cover what a size 000 wardrobe needs to handle, which also makes 000 a practical choice when you are buying for someone else’s newborn.
Buying Size 000 as a Baby Gift
If you are choosing a gift for a newborn, size 000 is a more practical choice than Newborn (NB) or 0000 for a simple reason: most babies fit it from birth and stay in it for the first two months. A gift in 000 has a much higher chance of being worn before the baby grows past it.
Practical gift suggestions in size 000:
• 2–3 bodysuits (short-sleeve for summer, long-sleeve for year-round use)
• 1–2 growsuits (useful immediately for sleep)
• A muslin wrap (versatile and not size-specific — adds value without sizing risk)
Signs It’s Time to Move Up from Size 000
Once your baby is wearing their 000 wardrobe — whether bought for themselves or received as a gift — the next thing most parents wonder is when to size up. Size up when you see these signs, and do not wait until a garment becomes visibly uncomfortable:
• The crotch snaps are difficult to fasten or will not reach the correct position
• Red marks appear on the shoulders, inner thighs, or around the waist after removing the garment
• Sleeve length or leg length leaves a noticeable gap above the wrist or ankle
• On a growsuit, the foot section is fully filled, and your baby's toes are pressing against the end
• Your baby’s weight is at or past 6 kg
One size change does not mean all garments change at once. Babies are proportioned differently, and a 00 may work for bodysuits before it works for growsuits — or vice versa. Check each garment type independently rather than switching everything at the same time.
Frequently Asked Questions
What does size 000 mean in Australia?
Size 000 is the standard newborn size in Australia, intended for babies weighing approximately 3–6 kg and measuring 57–62 cm. For most babies born at average birth weight, it fits from birth and is the starting point for a newborn wardrobe.
Is size 000 the same as Newborn (NB)?
Usually, yes — AU size 000 corresponds roughly to the international Newborn / NB label. That said, individual brands cut their garments differently, so it is worth checking each brand's size chart rather than assuming a direct match.
Do I actually need to buy size 0000?
For most babies, no. Size 0000 is intended for premature or very small newborns (under 4 kg). If your baby arrives at average birth weight, they may never wear 0000 comfortably. Keeping one or two pieces as a backup is sensible, but building the starter wardrobe in 000 is the practical default for most families.
How many size 000 outfits do I need?
A working starting point is 8–10 bodysuits and 4–6 growsuits. Plan for two to three full outfit changes per day in the first weeks — some days will need more due to spit-up and nappy leaks. This quantity covers a two-to-three-day laundry cycle without running short.
What's the difference between size 000 and size 00?
Size 000 fits babies roughly 3–6 kg (0–3 months). Size 00 is the next step up, intended for babies around 6–8 kg (3–6 months). Once a baby passes 6 kg, crotch snaps and shoulder seams in 000 will start to feel tight. That is the signal to move to 00. Because sizing can vary slightly between brands, checking the brand’s own size guide is always worthwhile before buying.
Using the Right Size Makes the First Weeks Easier
The key principle is straightforward: use weight and body length to choose a size, not the age printed on the label. For most Australian newborns, size 000 is the right starting point — it fits from birth, has the longest wear window of any single newborn size, and is the size where the majority of daily outfit changes actually happen.
The pieces that see the most use during the 000 stage are the bodysuits and growsuits. Both sit directly against your baby’s skin for hours at a time — which is why fabric is worth getting right from the start.
