It is on the smaller side, closer to an 8 than 10, in general a size 10 fits loosely on my daughter, and based on her dimensions I picked the M (8-10) but it could have been a bit longer, it is very stretchy so it fits, but it could have been longer to accommodate the size 10. It looks beautiful on, its just a little shorter than I thought it would be, the long side does not reach her knee and in the picture it shows the long side past her knee. I would recommend to get the next size up.
This dress is pretty but was damaged when we received it. There was a run going across the dress and a black spot on it. It also runs very small as it is snug on my daughter. She could probably only wear it once for her dance performance and that's about it. Felt like a waste of money!
The picture does not do this dress justice. It is very beautiful in person! My daughter looks and feels like a Princess in it. Luckily the day it arrived she also had lyrical dance practice that night so she was able to wear it right away. I am so glad I purchased this for her. My daughter is a small sized 10 year old so I bought her the size 8 to 10. If your daughter is an average sized 10 year old def buy next size up.