Baby Clothes Sizes Australia: Complete Guide (0000 to Size 2)

Australian baby sizing looks confusing at first. Sizes count down before they count up, and the same number can mean different things in different shops. Once you understand the logic, it is simple.

This guide explains what each size means, the age and weight it roughly fits, and how to choose so you are not left with a drawer of clothes your baby never wore.

How Australian baby sizes work

Australian baby clothes are sized by age, using a run of zeros for the smallest babies. The more zeros, the smaller the size. So 0000 is the tiniest, then 000, then 00, then 0, and after that it moves to whole numbers like 1 and 2.

The number is a guide to age, but babies vary enormously in size, so treat it as a starting point rather than a rule. A big three month old and a small three month old can be two sizes apart.

Australian baby clothes size chart

Use weight and height first and age second. If your baby is heavier or taller than the age band suggests, go by the measurement.

What size to buy before the baby arrives

It is tempting to stock up on newborn size, but many babies grow out of 0000 within a couple of weeks, and some are born too big for it. A safer plan is to buy a few pieces in 0000 and more in 000, so you are covered whether your baby arrives small or solid.

Should you size up or size down?

When in doubt, size up. There are three reasons this almost always wins:

• Babies grow fast. A perfect fit today can be tight in a fortnight.
• Organic cotton shrinks a little. Natural fibres tighten slightly on the first wash, so a touch of room helps.
• Comfort and safety. A slightly roomy suit lets your baby move and does not dig in, though it should not be so large that it bunches around the face.

Reading the weight and height instead of the age

The most reliable way to choose is to weigh and measure your baby and match that to the chart, rather than trusting the month on the tag. Weigh your baby, note their length, and pick the size where both fall inside the band. If they sit between two sizes, take the larger one.

Why the same size fits differently across brands

You may notice a size 000 from one label fits your baby while a 000 from another is snug. This is normal. Brands cut to slightly different measurements, and a piece made for sleep is often roomier than a fitted outfit. This is exactly why the height and weight columns matter more than the number on the tag. When you find a brand whose sizing suits your baby, staying with it for base layers saves a lot of guesswork, because you already know how their next size up will fit.

Signs your baby has outgrown a size

Rather than watching the calendar, watch the clothes. It is time to move up a size when:

• The zip or studs strain to close, or leave marks on the skin.
• Sleeves and legs sit well short of wrists and ankles.
• A suit looks stretched across the tummy or shoulders.
• Foot cuffs curl your baby's toes rather than covering them loosely.

Catching this early keeps your baby comfortable and stops a favourite piece being worn uncomfortably for weeks past its time.

A simple starter plan by size

For a newborn, a workable starting wardrobe might be a few pieces in 0000 and a slightly larger set in 000, then top up in 00 as your baby grows. Our newborn baby clothes checklist breaks down exactly how many of each item you actually need, so you buy once and buy well.

Frequently asked questions