The Flesch Reading Ease score is the most widely-cited readability formula in English-language writing. Most word processors, SEO plugins, and writing tools surface it. Few of them explain what it means, how it's computed, or — most usefully — how to improve it deliberately.
What the Flesch Reading Ease score is
Flesch Reading Ease is a numeric score from 0 to 100 that estimates how hard a passage is to read in English. Higher scores are easier; lower scores are harder. The score was developed by Rudolf Flesch in 1948 for the US Navy and refined for civilian use in the 1970s. Its companion metric, Flesch–Kincaid Grade Level, expresses the same data as a US school grade.
The Flesch Reading Ease formula
206.835 − 1.015 × (total_words / total_sentences) − 84.6 × (total_syllables / total_words)Two ratios drive the score: average sentence length and average syllables per word. The asymmetry is the practical insight: word complexity hurts your score five to ten times more than sentence length. If you want a higher Flesch score, use shorter words first.
Flesch score bands
| Score | Level | Audience |
|---|---|---|
| 90–100 | Very easy | 5th-grade students |
| 60–70 | Plain English | 8th–9th-grade — recommended for online writing |
| 30–50 | Difficult | College students |
| 0–30 | Very difficult | University graduates; legal/academic prose |
For most online writing, target 60–70.
Three changes that move the score most
- Replace polysyllabic words with shorter synonyms. The largest single lever. utilize → use; demonstrate → show; approximately → about.
- Break sentences over 25 words at coordinating conjunctions.
- Cut "very", "really", "quite" — most adverbs and intensifiers.
For the full nine-edit list: How to improve your readability score.
Try it
Paste any passage into the Word Counter and the Flesch Reading Ease score appears in the sidebar in real time. For all six readability scores at once (Flesch, Flesch–Kincaid, Gunning Fog, SMOG, ARI, Coleman–Liau), expand "All readability scores".
Related: The Readability Guide.
