General guidelines of the measurements we use for our couture collections: 
Princess Palais Royal Couture Flower girl Dresses Size Chart Miele Moda Luxury Fashion
For help measuring your child correctly, please check this article we wrote on our Blog to help you get the most accurate measurements in a fast and easy way. 
If you have further questions, please contact us prior to placing an order so we can assist you in selecting the perfect size for your little flower girl.