Readability Checker
Flesch Reading Ease and Flesch–Kincaid grade level, scored live as you edit — with a plain-English verdict so the numbers mean something immediately.
Type at least one full sentence to score readability.
The formulas, in the open
Reading Ease = 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words); Flesch–Kincaid Grade = 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59. Both reward the same two habits — shorter sentences and shorter words — which is why the fastest route to a better score is splitting your longest sentence and swapping one latinate word ("utilize") for its plain twin ("use").
A before-and-after example, with real scores
Score this sentence: "The implementation of the aforementioned recommendations necessitates comprehensive organizational restructuring." The checker returns a Reading Ease of −125 and a Flesch–Kincaid grade of 33 — yes, negative, and yes, grade 33. The scale is conventionally described as 0–100, but the formula is unbounded, and ten words carrying 38 counted syllables simply break through the floor. Now score the rewrite: "To follow this advice, we must reorganize the company." Nine words, 15 syllables: Reading Ease 57, grade 7.6. Same meaning, roughly 180 points apart — almost all of it from syllables-per-word, which the formula weights about 80 times more heavily than sentence length. That is the practical lesson of Flesch scoring: shortening words moves the needle faster than shortening sentences.
Where the score misleads
Three situations deserve skepticism. Short texts: under about a hundred words, one long sentence or one polysyllabic name can swing the score wildly — the formulas were calibrated on passages, not headlines. Structured text: headings and bullet points without ending punctuation merge into neighboring sentences, inflating sentence length and deflating the score; score your running prose, not your outline. Simple-word jargon: a text can score "easy" while being conceptually brutal ("short rate risk beta") because the formula reads syllables, not meaning. Readability thresholds also appear in regulation — several US states have long required insurance policy forms to meet minimum Reading Ease scores, for example — but statutory tests specify their own counting rules, so verify against the applicable statute rather than any online checker, including this one.
Frequently asked questions
What does the Reading Ease score mean?
A 0–100+ scale where higher is easier: 60–70 is "plain English" an 8th–9th grader follows comfortably, 30–50 reads like college material, and below 30 is dense academic or legal prose. Most successful general-audience writing lands between 60 and 80.
And the Flesch–Kincaid grade?
The same ingredients — sentence length and syllables per word — restated as a US school grade. An FK grade of 8 means an average 8th grader can follow it. Newspapers famously target around 9–11; plain-language guidelines for public information often require 8 or below.
How accurate is the syllable counting?
It is a heuristic (vowel groups with a silent-e rule), as in virtually every automated checker — English syllabification has genuine exceptions. Scores typically land within a few points of hand-computed values; treat the score as a strong signal, not a laboratory measurement.
Should I always aim for a higher ease score?
Aim for your audience. Simplifying a physics paper to 5th-grade prose destroys precision, and pushing marketing copy to graduate density destroys conversion. The score tells you where you are; where you should be depends on who is reading.
Scoring happens locally in your browser — nothing you paste is transmitted or stored. Syllable counting is heuristic, as documented on the methodology page.