Flesch-Kincaid Readability Score Calculator
Paste or type any text below to instantly calculate its Flesch Reading Ease score and Flesch-Kincaid Grade Level, helping you understand how easy or difficult the text is to read.
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Formulas
Flesch Reading Ease (FRE):
FRE = 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words)
Flesch-Kincaid Grade Level (FKGL):
FKGL = 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59
Reading Ease Score Interpretation:
| Score | Difficulty | Typical Reader |
|---|---|---|
| 90–100 | Very Easy | 5th grade |
| 80–90 | Easy | 6th grade |
| 70–80 | Fairly Easy | 7th grade |
| 60–70 | Standard | 8th–9th grade |
| 50–60 | Fairly Difficult | 10th–12th grade |
| 30–50 | Difficult | College level |
| 0–30 | Very Confusing | College graduate |
Assumptions & References
- Syllable counting uses a heuristic vowel-group method; results may vary slightly from manual counts for irregular words.
- Sentences are detected by splitting on
.,!, and?punctuation marks. - Only alphabetic words (including hyphenated and apostrophe words) are counted; numbers and symbols are excluded.
- A minimum of 10 words is required for a statistically meaningful score.
- The Flesch Reading Ease formula was developed by Rudolf Flesch and published in The Art of Readable Writing (1949).
- The Flesch-Kincaid Grade Level formula was developed by Kincaid et al. for the U.S. Navy in 1975 (NPRDC Technical Report 8-75-15).
- Both formulas are widely used in education, publishing, government, and healthcare to assess text accessibility.
- The U.S. Department of Defense uses FKGL ≤ 8 as a plain-language writing standard.