For children we have a unisex based size chart from NB-7Y. After size 7Y, we make a split into in the pink chart (7Y-14Y, Adult) and petrol chart (7Y-16Y, Adult). The base of the pattern is always shown with the two lines on the first picture of the pattern.
The pink chart has narrower shoulders, smaller waists and hips. The petrol chart based patterns will have for e.g. broader shoulders, smaller hips.
We have made a “how to measure” blog.
Pink Adult Size Chart Size 2-20 (New Chart)