A size 6 in clothing often corresponds to a child around 4-5 years old, weighing 45-50 lbs (20-23 kg), while a size 6 in women's shoes is typically a toddler shoe (around 2 years old) or a youth size 6 in sneakers, but in adult women's clothes, it's a size 6, which is Small or Medium depending on the brand, so "size 6" varies greatly by item and age group.
An AU size 6 is a small size, roughly equivalent to a US size 2-4 (women's clothing) or a US size 6 (men's shoes), and a European size 32-34 for clothing, or 36-37 for women's shoes, but it's crucial to check the specific brand's size chart for accurate measurements, as conversions vary, especially for shoes where it's about 36 EU/US size.
00 thru size 2 is considered extra small to small. Size 4- 8 is about a medium and 10–14 is considered large. 16–18 is XL and above that is what is usually considered “plus” sizes. Baby's clothing is sized by the child's age- Newborn, 3mos, 6mos, etc.
It's equivalent to a US size 6. The measurements associated with this size are: Bust: 86-89 cm (33.5"-35"); Waist: 69-72 cm (26.5"-28"); and.
Youth XS: Size 5-6. Youth S: Size 6-7. Youth M: Size 8-10. Youth L: Size 12-14.