Flesch–Kincaid Grade Level calculator
The Flesch–Kincaid Grade Level turns sentence length and word length into a US school grade. A score of 8 means an average eighth-grader (about 13–14 years old) should follow the text.
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The Flesch–Kincaid Grade Level formula
0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59
Many style guides aim for grade 8 or below for public information. US federal plain-language guidance and most health-literacy advice point in the same direction.
J. Peter Kincaid and colleagues derived it for the US Navy in 1975 from Flesch’s earlier work. It is the grade shown in Microsoft Word’s readability statistics.
What your score means
| Score | Reading level |
|---|---|
| 1–5 | Elementary school |
| 6–8 | Middle school – most public information |
| 9–12 | High school – newspapers, most essays |
| 13–16 | College |
| 17+ | Graduate / professional |
Drag the inputs, watch the score
The formula only “sees” these numbers. Change them and notice which one moves the score most.
Grade level (higher = harder)
9.1
US grade 9
Questions people ask
What grade level should I write at?
For the general public, grade 7 to 9. For patient information, many health bodies recommend grade 6 to 8. University essays usually land between 12 and 16, and that’s fine for their audience.
Why does my score change when I split one sentence into two?
Words per sentence is one of the two inputs, weighted by 0.39. Halving an average 30-word sentence to 15 words lowers the grade by almost 6 levels.
Is the Flesch–Kincaid grade accurate?
It is a rough guide. It counts syllables, not meaning, so a short sentence full of rare jargon can score as easy. Use it alongside your judgement and, ideally, a real reader.