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Reading Level Analyzer

Flesch Reading Ease + Flesch-Kincaid grade level + word and sentence stats. Runs in your browser; nothing is sent to a server.

Flesch Reading Ease
47
Difficult (college)
Flesch-Kincaid Grade
9.4
US grade level
Words
33
Sentences
3
Words / sentence
11
Syllables / word
1.76

How the Flesch-Kincaid formulas work

Two related but distinct formulas, developed by Rudolf Flesch (Reading Ease) and J. Peter Kincaid (Grade Level). Both use the same inputs — average sentence length and average syllables per word — but scale the output differently.

Flesch Reading Ease = 206.835 − 1.015 × (words/sentences) − 84.6 × (syllables/words). Higher is easier.

Flesch-Kincaid Grade Level = 0.39 × (words/sentences) + 11.8 × (syllables/words) − 15.59. Output approximates US school grade level required.

When to use which

  • · Reading Ease (0-100) — useful for marketing copy, content articles, anywhere you want a quick “is this approachable?” check. Target 60+ for general audience.
  • · Grade Level — useful for educational materials, government documents, ESL content. Target 6-8 for general public; 12+ for academic.

Reading Ease bands

  • · 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)
  • · 0-30: Very difficult (college graduate / specialist)

Use cases for teachers

  • · Check whether a quiz stem is at the right reading level for your students.
  • · Calibrate ESL reading materials to learner CEFR level.
  • · Verify your handouts aren't accidentally graduate-level.
  • · Compare draft quiz questions against the source textbook's reading level.

Limitations

The formulas measure surface complexity (sentence length and syllable count) — they don't measure conceptual difficulty. A sentence can score “easy” on Flesch-Kincaid while discussing quantum mechanics. Use the metric as a quick check, not a definitive readability verdict.

The English-language version is what most editors use; equivalents exist for other languages (LIX for Swedish, SMOG for English alternative, Lesbarkeitsindex for German).

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