How to use Readability checker
- 1
Paste your draft
Add a paragraph or a whole article — at least 100 words gives stable scores.
- 2
Read the verdict
The panel shows the average US grade level in plain words, the Flesch Reading Ease score and each formula's result.
- 3
Fix the highlights
Shorten red and amber sentences, swap wordy phrases for the suggested plain ones and rewrite passive sentences, then watch the grade drop.
Limits and Pro
Free and unlimited with no sign-up. Highlights stay live while you type in documents of up to about 30,000 characters (5,000 words); longer texts are re-scored a moment after you pause.
Pro removes ads; all seven formulas and the highlights are free. See Pro
About Readability checker
Readability formulas estimate how much schooling a reader needs to follow a text comfortably, using things that can be counted: sentence length, syllables per word, letters per word and how many words fall outside a list of familiar vocabulary. This checker runs the seven formulas editors, teachers and plain-language reviewers rely on — Flesch Reading Ease, Flesch–Kincaid Grade, Gunning Fog, SMOG, Coleman–Liau, the Automated Readability Index and the New Dale–Chall score — and averages the grade levels into one plain verdict.
Every score uses the published coefficients, so the numbers can be compared with other tools that use the same counts. Syllables are counted with a well-tested English heuristic plus corrections for words it tends to get wrong, such as “poem” and “going”. Dale–Chall checks each word against the 3,000-word familiar list and accepts regular plurals and verb endings, and Gunning Fog ignores proper nouns, hyphenated compounds and syllables added only by -es, -ed or -ing, as Gunning specified.
As you type, the editor highlights hard sentences in amber and very hard ones in red, plus passive constructions, -ly adverbs and wordy phrases that have plainer alternatives (“utilize” → “use”). Each kind of highlight can be switched off, and the suggestions panel lists the worst sentences first.
Formulas only measure surface features. A short sentence full of jargon can score well and still confuse people, and the scores are calibrated for English prose, so poetry, code and other languages give unreliable results. SMOG in particular is designed for samples of 30 sentences.
Privacy
The analysis — sentence splitting, syllable counting and the word-list check — runs inside this page once its scoring code has loaded; your writing is never sent to a server. The draft and your highlight preferences are kept in this browser's local storage until you clear them.
Features
Seven standard formulas
Flesch, Flesch–Kincaid, Gunning Fog, SMOG, Coleman–Liau, ARI and New Dale–Chall with published coefficients.
Hemingway-style highlights
Hard and very hard sentences, passive voice, adverbs and plainer word choices, each switchable.
Dale–Chall word list
Every word is checked against the 3,000 familiar words, with plurals and verb forms recognised.