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The Lexile Analyzer uses an algorithm to evaluate the reading demand — or text complexity — of books, articles and other materials. The Lexile Analyzer measures the complexity of the text by breaking down the entire piece and studying its characteristics, such as sentence length and word frequency, which represent the syntactic and semantic challenges that the text presents to a reader. The outcome is the text complexity, expressed as a Lexile measure, along with information on the word count, mean sentence length and mean log frequency.

Generally, longer sentences and words of lower frequency lead to higher Lexile measures; shorter sentences and words of higher frequency lead to lower Lexile measures. Texts such as lists, recipes, poetry and song lyrics are not analyzed because they lack conventional punctuation.

Free Registration for Educators

Access to the Lexile Analyzer is free for educators who are registered Lexile.com users. Initially, you will have a 1000-word limit. If you’d like to analyze longer pieces of text, you can request access to the Professional Lexile Analyzer®. Please submit your request through the My Account portal. Educators can upgrade for free.

Sign In to access the Lexile Analyzer. 


Spanish Lexile Analyzer®

The Lexile Analyzer works the same way for Spanish text. You need to register to use the Spanish Lexile Analyzer. Already registered? Please sign in.

Now More Precise!

Learn how the Lexile Analyzer was recently enhanced to more precisely measures reading materials used in K–2 classrooms.

Find out more