Readability & Reading-Speed Lab

Writing Style

Avg. sentence length 18 words

Word complexity 1.50 syl/word

Sentence variety 40%

Reader's base speed 225 wpm

Readability

Flesch Reading Ease — —

Flesch-Kincaid grade

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Est. read time (article)

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Now reading sentence 1 / 24

How it works

The Flesch Reading Ease and Flesch-Kincaid Grade Level formulas score English prose from just two averages: words per sentence (ASL) and syllables per word (ASW). They're the same formulas built into Microsoft Word, Hemingway App and most SEO editors:

Reading Ease = 206.835 − 1.015·ASL − 84.6·ASW
  90-100 very easy · 60-69 standard · 0-29 very confusing

Grade Level  = 0.39·ASL + 11.8·ASW − 15.59
  (approximate US school-grade needed to read it easily)

Each bar in the 3D terrain is one of 24 sentences in a sample article; its height and color encode that sentence's own grade level (green = easy, red = hard) once your sliders' averages are spread across sentences with some natural variety.

The glowing reader sphere walks the article sentence by sentence. Its dwell time on each sentence is modeled as words ÷ effective speed, where effective speed falls as local difficulty rises — a simplified stand-in for the well-documented real effect that harder text slows silent reading speed, not a universal constant.

Sentence length / word complexity — the two inputs to both formulas; push either up and the terrain grows taller and redder.
Sentence variety — how much individual sentences deviate from the averages (a monotone vs. a varied article).
Presets — News, Academic and Ad-hook styles set realistic combinations seen in real editorial guidelines.

Easy sentence Hard sentence Reader

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