A Complete Guide to Baby Clothing Sizes for Australian Parents

If you've ever looked at a baby clothing tag and thought "Wait, what size is this actually?" — you're not alone. Australian baby clothing sizes usually correspond to an approximate age range, but babies grow at different rates and sizing can vary between brands.

The easiest way to think about baby sizing is this: use the size, height and weight guides together rather than relying on age alone. A baby's measurements can often tell you more about which size is likely to fit than their age.

Australian Baby Clothing Size Chart

The table below is a practical guide to baby clothing sizes commonly used by major Australian retailers. These measurements are approximate rather than a universal Australian standard, and individual brands can vary.

These figures are a guide, not a universal sizing standard. Current size charts from major Australian retailers including Target, BIG W and Cotton On Kids use very similar size, age, height and weight relationships, although measurements can differ slightly between brands.

 

How Do Australian Baby Clothing Sizes Work?

Australian baby clothing commonly uses a sequence of zeros for the smallest sizes before moving into sizes 1, 2 and beyond. The more zeros there are, the smaller the size.

0000 is commonly used for newborn clothing, 000 for approximately 0–3 months, 00 for 3–6 months and 0 for 6–12 months. Size 1 commonly corresponds to around 12–18 months and size 2 to around 18–24 months.

You may also encounter 00000 for tiny or early babies and 000000 for premature babies. Not every brand carries these smaller sizes.

The important point is that the age range is only a guide. Height, weight, body proportions, garment design and differences between brands can all affect which size fits best.

Is Height or Weight More Useful Than Age When Choosing Baby Clothes?

Height and weight can often be more useful than age when choosing a baby clothing size. Two babies who are both six months old can have quite different measurements, so choosing entirely by age can produce a poor fit.

If a brand provides a size chart, compare your baby's current height and weight with its measurements. You may find that your baby's age points towards one size while their measurements suggest another.

Height can be particularly useful for garments where overall body or leg length matters, while weight can provide another useful indication of general size. Neither measurement guarantees a perfect fit because babies can have different proportions, but together they provide considerably more information than age alone.

Do Baby Clothing Sizes Vary Between Australian Brands?

Yes. A size 00 from one brand won't necessarily fit exactly like a size 00 from another.

Australian retailers use broadly similar age ranges, but the actual measurements and cut of individual garments can differ. For example, current Australian size charts show some variation in the suggested height for sizes 0, 1 and 2 even where the age and weight guides are very similar.

This is particularly relevant when shopping secondhand. Instead of buying an entire wardrobe from one brand, you might have Bonds, Target, Cotton On Kids, Purebaby and other brands together in the same size.

If your baby hasn't worn a particular brand before, check that brand's current size chart where possible rather than assuming its size label will fit identically to another brand.

Tips for Choosing the Right Baby Clothing Size

• Use height and weight as well as age — if the measurements point towards a different size from the age range, don't assume the age label must be right
• Check the brand's own size guide — particularly when buying a brand your baby hasn't worn before
• Consider the type of garment — a little extra room in an everyday top is different from an item where correct fit is important
• Think ahead to the season — if you're buying clothing in advance, consider what the weather is likely to be when your baby reaches that size
• Look at the actual fit — neck openings, sleeves, waistbands, body length and leg length can all matter
• Don't worry if the label doesn't match your baby's age — the goal is clothing that fits appropriately, not keeping your baby in the size supposedly associated with their age

What If Your Baby Is Between Sizes?

For ordinary everyday clothing, moving to the larger size can sometimes provide more growing room, but “always size up” isn't a good universal rule.

Check how the garment actually fits. Sleeves shouldn't create a problem for movement, neck openings shouldn't be excessively loose, and pants shouldn't be so long that they interfere with crawling or walking.

Fit deserves particular attention with children's nightwear. Australian product-safety guidance notes that loose-fitting nightwear has a greater risk of catching fire, so deliberately buying oversized clothing isn't appropriate for every type of garment.

The better question isn't simply “Which size should my baby's age be?” It's “Which size fits my baby appropriately in this particular garment?”

Should You Buy Baby Clothes in the Next Size Up?

Having some clothes ready in the next size can be useful. Buying an entire wardrobe several sizes ahead is much riskier.

Babies don't all grow at the same rate, and seasons don't always line up neatly with predicted sizes. A winter jacket bought several sizes ahead may turn out to fit in spring, while a pile of summer clothes bought in advance may be outgrown before the warm weather arrives.

For versatile everyday basics, buying selected items in the next size can make sense. For expensive, strongly seasonal or fit-sensitive garments, there is less reason to get too far ahead.

This same principle applies beyond the baby years. Our guide to building a kids' wardrobe on a budget using secondhand clothes looks at buying ahead, wardrobe quantities and buying for what your child will actually use.

Think About the Season When Buying Ahead

Season is one of the easiest things to overlook when buying baby clothes in advance.

Imagine buying a heavily padded size 0 jacket because it's a bargain while your baby is still wearing size 000. By the time they reach size 0, it may be the middle of summer.

The further ahead you're buying, the greater the uncertainty becomes. Basics that work across seasons can be useful purchases, but for strongly seasonal garments such as heavy coats and swimwear, think about when your baby is likely to reach that size, not simply whether they'll eventually reach it.

Does Buying Secondhand Make Sense When Babies Change Sizes So Quickly?

Baby clothing can be particularly well suited to buying secondhand because babies may move through several clothing sizes while individual garments still have plenty of useful life remaining.

Buying preloved can make it less expensive to keep up with changing sizes, particularly for clothes that may only fit for a relatively short period.

There is one extra sizing consideration when buying secondhand: a basket containing several different brands may contain garments that all say size 00 but don't all fit at exactly the same time.

If you're deciding where secondhand offers particularly good value, see our guide to what kids' clothes are best to buy secondhand.

Quick Guide to Australian Baby Clothing Sizes

If you just need the short version:

000000 = Premature baby, 2.5 kg
00000 = Tiny/early baby, 50 cm / 3 kg
0000 = Newborn, 56 cm / 4 kg
000 = 0–3 months, 62 cm / 6 kg
00 = 3–6 months, 68 cm / 8 kg
0 = 6–12 months, 76–80 cm / 10 kg
1 = 12–18 months, 84–86 cm / 12 kg
2 = 18–24 months, 91–92 cm / 13.5–14 kg

Remember that these are approximate guides. When a brand provides its own measurements, check those as well.

Frequently Asked Questions

What size is newborn in Australia?
Size 0000 is commonly used for newborn baby clothing in Australia, with major Australian retailer charts typically associating it with babies around 56 cm tall and 4 kg. Some babies will need a smaller or larger size depending on their measurements.

What size is 000 in baby clothes?
Size 000 commonly corresponds to approximately 0–3 months, around 62 cm in height and around 6 kg in weight. Treat these figures as a guide because individual brands and babies vary.

What size is 00 in baby clothes?
Size 00 commonly corresponds to approximately 3–6 months, around 68 cm in height and around 8 kg in weight.

What size is 0 in baby clothes?
Size 0 commonly corresponds to approximately 6–12 months and around 10 kg. Current Australian retailer charts vary somewhat on height, with guides around 76–80 cm.

What size is 1 in baby clothes?
Size 1 commonly corresponds to approximately 12–18 months and around 12 kg, with current retailer height guides around 84–86 cm.

What size is 2 in baby clothes?
Size 2 commonly corresponds to approximately 18–24 months, around 91–92 cm and approximately 13.5–14 kg.

Do Australian baby clothing sizes vary between brands?
Yes. Australian brands use broadly similar sizing conventions, but garment measurements and fit can differ. Use age as a starting point and compare height, weight and the brand's own size chart where possible.

Is age, height or weight best for choosing a baby clothing size?
Age is useful as a quick guide, but height and weight can give you more information about which size is likely to fit your baby. Using all three together, along with the brand's own measurements and the type of garment, is more useful than relying on age alone.

Should I size up when buying baby clothes?
Not automatically. For ordinary clothing, the larger size may provide more growing room if your baby is between sizes, but the garment still needs to fit appropriately. Correct fit can be particularly important for garments such as children's nightwear.

How far ahead should I buy baby clothes?
Keeping a few useful everyday items in the next size can be practical, but buying an entire wardrobe several sizes ahead is riskier because babies grow at different rates and the clothing may not suit the season when it eventually fits.

The Bottom Line

Australian baby sizing becomes much easier once you know the basic sequence, but the age on the label is a guide, not a rule.

Start with the usual Australian size, then look at height and weight, check the individual brand's measurements where available, consider the type of garment and pay attention to how the clothing actually fits your baby.

And if your six-month-old fits size 00 in one brand and size 0 in another, there's nothing unusual about that. The useful size is the one that fits.

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