Free Lexile Score Calculator
Estimate a Lexile reading measure from sentence length and word frequency factors. Lexile scores match readers to appropriately difficult texts.
Log frequency from word corpus (typically 2.5–5.0)
Estimated Lexile Score
750
Approximate Grade Level8
Sentence Complexity Factor1.50
Estimated Lexile Score vs Average Sentence Length (words)
How to Estimate a Lexile Score
Lexile measures are based on sentence length (syntactic complexity) and word frequency (semantic difficulty).
Simplified Formula
Lexile ≈ 200 x (ASL / 10) - 100 x MLWF + 800
Where ASL = Average Sentence Length and MLWF = Mean Log Word Frequency.
Higher Lexile scores indicate more difficult text. Typical range: 200L (early reader) to 1600L (advanced).
Example Calculation
A text has average sentence length 15 and mean log word frequency 3.5.
- 01Lexile = round(200 x 15/10 - 100 x 3.5 + 800)
- 02= round(300 - 350 + 800) = round(750) = 750L
- 03Approximate grade level = round(750 / 100) = 8