Flesch–Kincaid grade level calculator
Aim for grade 8 or lower for anything the general public reads, and grade 6–8 for business email. A score of 8.0 means a typical US eighth grader (age 13–14) could understand the text.
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Flesch–Kincaid Grade Level
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Formula: 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59
- Words
- 0
- Sentences
- 1
- Syllables
- 0
How to read the FK grade score
| Score | Meaning |
|---|---|
| 5 or below | Very easy: understood by most 10–11 year olds |
| 6–8 | Plain English: the target for email, web copy and public information |
| 9–10 | Fairly difficult: fine for engaged professional readers |
| 11–12 | Difficult: typical of specialist reports |
| 13–16 | College level: academic and technical writing |
| 17+ | Graduate level: legal and scientific text |
Lower scores mean easier text.
Where the Flesch–Kincaid Grade Level comes from
Developed by J. Peter Kincaid and colleagues in 1975 for the US Navy, re-weighting Rudolf Flesch’s Reading Ease inputs so the result reads as a US school grade. It is built into Microsoft Word and is required for some US insurance and government documents.
Other readability formulas
- Flesch Reading Ease: 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words)
- Gunning Fog Index: 0.4 × [(words ÷ sentences) + 100 × (complex words ÷ words)]
- SMOG Index: 1.043 × √(polysyllables × 30 ÷ sentences) + 3.1291
- Coleman–Liau Index: 0.0588 × L − 0.296 × S − 15.8 (L = letters per 100 words, S = sentences per 100 words)
- Automated Readability Index: 4.71 × (characters ÷ words) + 0.5 × (words ÷ sentences) − 21.43
Questions people ask
What is a good Flesch–Kincaid grade level score?
For the general public, 8 or lower. For business email, 6 to 8. Specialist reports can sit at 10 to 12. Lower is easier; there is no prize for a high grade.
How do I calculate my Flesch–Kincaid grade level?
Count words, sentences and syllables. Then compute 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59. Example: 100 words, 5 sentences, 140 syllables gives 0.39 × 20 + 11.8 × 1.4 − 15.59 = 7.8 + 16.52 − 15.59 = 8.7. Or paste the text above and it is calculated for you.
How do I lower my Flesch–Kincaid grade level?
Shorten sentences and use shorter words. Each extra syllable per word costs 11.8 grades per word on average, so swapping “utilize” for “use” or “approximately” for “about” helps far more than you expect. Splitting a 30-word sentence in two also drops the score.
Why do different tools give different grade levels?
Syllable counting is an estimate, and tools split sentences differently (for example at semicolons, lists or abbreviations). Differences of half a grade to a grade between tools are normal.