Please check the description of my products for full sizing details and the pictures for sizing charts, but here's a rough guide for our best selling items:
Pinafores.These are a generous fit. If you want it to fit well you may want to size down. If you want room to grow I would purchase the current size your child wears.
These are much more fitted especially around the chest. We recommend sizing up, especially if you want to allow room to layer long sleeves underneath. The sleeves can be rolled up if they are too long to allow room to grow.
Please contact me if you have any other questions about sizing.