Please view the document below for a Reading Correlation chart. I have also listed two websites you can visit in order to find grade level equivalent books.
Here is how this works:
If your child is on a reading level 8, by looking at the Correlation chart, you will see that is a grade equivalency of 1.3 (first grade, third month of school).
You can then visit one of the websites below to search for books that are a 1.3 grade level. Then, your child can take that list to the library and check out books on their level! As a guideline, I suggest, if your child is a 1.3, they would benefit from reading books at a 1.0-1.6 reading level.
I hope this helps your child in choosing books that are "just right" for them!