It may be difficult to find out what size snowsuit to buy, as the child should be able to fit it the whole season. You can therefore tend to buy it a number too large so it does not get too small, but this can inhibit the child's freedom of movement and the ability to keep warm.
Therefore, the kids in LEGO® Wear Kids LAB have made this movie so you can see how to find the right size for your child.
Measure the height for your child and find the size that close or equal to the number. You can also see the size in the size chart on this page.
When the child has the snowsuit on, you can see if the child has a good room to grow and move in it. Check if there is room for a good handful of loose material over the shoulder or in the crotch, corresponding to around 10 centimetres.