Score your text on the Flesch Reading Ease scale (0–100). Higher means easier. Get a plain‑English category, ideal range, and per‑sentence breakdown.
Built and maintained by Paul Clark, Redmoon Software · Last verified · Sources
Use Flesch Reading Ease when you need a single intuitive number to compare two pieces of writing — for example, your marketing copy vs. a competitor’s. It is the most widely understood readability score and is supported natively by Microsoft Word, so editors and stakeholders recognise it immediately.
Compared to Flesch–Kincaid Grade Level, Reading Ease is the inverse of the same input — easier to communicate to a general audience ("score of 70+") but less actionable than a grade level. Compared to Gunning Fog, Flesch is more forgiving of long sentences and harsher on multi-syllable words. For health-related text, prefer SMOG.
Flesch Reading Ease was developed by Rudolf Flesch in 1948 to measure how easy a piece of English text is to read.
The formula rewards short sentences and short words. Higher scores (90+) mean text a fifth-grader can read; very low scores (under 30) indicate academic prose.
It does not measure correctness, persuasiveness, or quality — only mechanical readability.
For general audiences aim for 60–70. Web copy and marketing often target 70+ for maximum reach. Academic writing typically scores 30–50.
The formula is 206.835 − 1.015 × (words/sentences) − 84.6 × (syllables/words). Lower numbers mean harder text.
No. The constants were calibrated on English. Use LIX or Coleman-Liau for European languages and treat results as approximate.
Only indirectly: longer words tend to have more syllables. For vocabulary-aware scoring use Dale-Chall.
Input
The cat sat on the mat. The sun was warm and the sky was blue.
Output
Flesch Reading Ease: 98.7 — Very easy (5th grade).
Twelve words, two sentences, all short and one syllable: average 6 words/sentence and ~1.05 syllables/word. The high score reflects very easy reading suitable for children.
The score is 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words). Those two subtracted terms are the whole model: average sentence length and average syllables per word. Everything else — vocabulary, structure, whether the argument makes sense — is invisible to it.
Look at the coefficients and you can see the formula's opinion. Syllables per word carries a weight of 84.6 against sentence length's 1.015, so word choice moves the number far harder than sentence length does. Adding one syllable to the average word costs about 85 points; adding one word to the average sentence costs one. That imbalance explains most surprising results: a passage of short sentences full of long words scores worse than long sentences of plain ones.
The scale is not a percentage and is not bounded. Text can score above 100 (very short words in very short sentences) or below zero, and both happen with real writing. Treat the bands as the useful part: 90+ reads at roughly 5th grade, 60–69 is the "standard" band most general audiences sit in, and below 30 is specialist prose.
There is no pronunciation dictionary behind this. Syllables are counted with vowel-group rules plus a set of exceptions — including the trailing "-le" case that turns "table" into two syllables rather than one. That heuristic is right on the overwhelming majority of English words and wrong on a predictable minority: names, loanwords, initialisms and anything with an unusual vowel cluster.
Because the syllable term is the heavily weighted one, a document full of proper nouns can be scored a grade or two harder than it reads. That is a limitation of every syllable-based formula, not of this implementation specifically, and it is the main reason character-based measures like Coleman–Liau and ARI exist.
The practical consequence: use the score to compare two drafts of the same document, where the vocabulary is similar and the error is consistent in both. Comparing two unrelated documents — especially across subject matter — asks the number to do something it cannot.
The method behind this tool, so you can check it rather than take it on trust.
Flesch, R. (1948). “A new readability yardstick.” Journal of Applied Psychology, 32(3), 221–233.
The original formula this score implements, weighting average sentence length against average syllables per word.
A grounded answer with score bands, real examples from journalism and fiction, and what scores to target for blogs, marketing, technical docs, and academic writing.
Three popular readability formulas, side by side. When each is the right tool, what they get wrong, and how to read disagreements between them.
U.S. grade level for your text.
Readability scoresPenalises complex (3+ syllable) words.
Readability scoresHealth & medical text grade level.
Readability scoresNo syllables needed — just characters.