The following website can help you determine a range of books that your child can be successful at reading and understanding.  www.lexile.com
 

A Lexile measure is a valuable piece of information about either an individual's reading ability or the difficulty of a text, like a book or magazine article. The Lexile measure is shown as a number with an "L" after it — 880L is 880 Lexile.

A student gets his or her Lexile reader measure from a reading test or program. For example, if a student receives an 880L on her end-of-grade reading test, she is an 880 Lexile reader. Higher Lexile measures represent a higher level of reading ability. A Lexile reader measure can range from below 200L for emergent readers to above 1600L for advanced readers. Readers who score below 0L receive a BR for Beginning Reader. In some cases, for readers, a BR code is followed by a number and L (e.g., BR150L). A Lexile reader measure of BR150L indicates that the Lexile measure of the reader is 150 units below 0L. The smaller the number following the BR code, the more advanced the reader is. For example, a BR150L reader is more advanced than a BR200L reader.

MAP data reports will list a lexile number for each student.  The Wildwood Media page also has lexile resources as well as the Destiny webpage.