You have everything at your fingertips to decide what size to buy. If things don't work out perfectly (and sometimes they don't) we'll exchange the items for the correct size - as long as they are unwashed and unworn with labels still intact.
Firstly - and the easiest way.
Look at your child, look in your child's wardrobe. What size casual clothes are you buying? What size school uniform are they currently wearing? Is it just right still? Has your child grown and so the uniform is getting too small? If your child has had a growth spurt and gone up two sizes in jeans then they probably will have gone up sizes in school pants too.
Secondly - Measure your child
Below are the size charts for each of the brands I stock.
Measure your child and then see where they fit on the chart.
If you don't have a tape measure use a piece of ribbon, or string, or wool or.... measure the child and then measure the length against a ruler.
Midford Sizing Guide: Updated size guide coming soon or visit the Midford Website https://www.midford.com.au/sizing-information