Work out reading level (lexile estimate) instantly with clear inputs, formula shown and shareable results.
The published Lexile theoretical logit combines sentence length and word frequency, then is rescaled by 180.1295 and shifted by -366.5714 to land on the Lexile scale. Lexile ranks text by two measurable properties rather than subject matter, which is why it can rate a short-sentence science text as easier than a long-sentence picture book.
Theoretical logit
logit = 9.82247 x ln(mean sentence length) - 2.14634 x mean log word frequency
Lexile measure
Lexile = logit x 180.1295 - 366.5714, reported to the nearest 5L
logit = 9.82247 x ln(mean sentence length) - 2.14634 x mean log word frequency. The published Lexile theoretical logit combines sentence length and word frequency, then is rescaled by 180.1295 and shifted by -366.5714 to land on the Lexile scale.
Lexile ranks text by two measurable properties rather than subject matter, which is why it can rate a short-sentence science text as easier than a long-sentence picture book.
Enter mean sentence length, mean log word frequency. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.