How to use the Readability Checker
- Paste your text into the box, or click Try a sample to see how it works.
- Read the headline grade level and verdict, then the six individual scores.
- Scroll to Where to simplify: long sentences are highlighted and complex words underlined.
- Edit your text in the box and watch the scores update until you reach your target.
Features
- Six standard formulas, including Flesch Reading Ease and Flesch-Kincaid
- An average grade level with a plain-English verdict
- Highlights sentences over 20 and over 30 words
- Underlines words with three or more syllables
- Averages for words per sentence, syllables and letters per word
- Runs in your browser; your text is not uploaded
What readability scores measure
Readability formulas estimate how much effort a text takes to read by counting two things that reliably make reading harder: long sentences and long words. They cannot judge whether your ideas are clear, well ordered or accurate, and they do not know which long words your readers already know. Treat them as a quick, objective check that points you to the sentences most worth rewriting.
The six formulas
| Score | Formula |
|---|---|
| Flesch 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 |
| Gunning Fog | 0.4 × [(words ÷ sentences) + 100 × (complex words ÷ words)] |
| SMOG | 1.043 × √(words of 3+ syllables × 30 ÷ sentences) + 3.1291 |
| Coleman-Liau | 0.0588 × letters per 100 words − 0.296 × sentences per 100 words − 15.8 |
| Automated Readability | 4.71 × (characters ÷ words) + 0.5 × (words ÷ sentences) − 21.43 |
All except Flesch Reading Ease give a US school grade: 8 means an eighth-grader, typically 13 to 14 years old, should follow it. The headline figure is the average of the five grade scores, which smooths out the quirks of any single formula. Coleman-Liau and ARI count letters instead of syllables, so they agree less with the others on text full of short technical terms.
Reading the Flesch score
| Score | Difficulty | Roughly |
|---|---|---|
| 90–100 | Very easy | 5th grade |
| 70–90 | Easy to fairly easy | 6th–7th grade |
| 60–70 | Plain English | 8th–9th grade |
| 50–60 | Fairly difficult | 10th–12th grade |
| 30–50 | Difficult | College |
| Below 30 | Very difficult | College graduate |
Higher is easier. Many plain-language guides suggest aiming for a grade level of about 8 for general audiences, and lower for health, safety or public service information.
How words and syllables are counted
Sentences end at a full stop, question mark, exclamation mark or line break, with common abbreviations such as “Dr.” and “e.g.” ignored. Syllables are estimated from groups of vowels, with corrections for silent endings such as the e in “make” and the -ed in “jumped”. The estimate is right for the large majority of English words but not all, which is one reason different checkers give slightly different scores. For the Fog index, words of three or more syllables count as complex unless they are names, hyphenated compounds, or only reach three syllables through -es, -ed or -ing.
How to raise your score
- Split long sentences. Anything highlighted over 20 words is a candidate; over 30 almost always reads better as two.
- Prefer short, common words: use for utilize, help for facilitate, about for approximately, start for commence.
- Use the active voice. “The team approved the plan” is shorter and clearer than “The plan was approved by the team.”
- Turn lists of items into bullet points instead of one long sentence.
Do not write for the score alone. Very short, choppy sentences can score well and still read badly. Listening to your text with Text to Speech is a good final check, and the Word Counter keeps an eye on length.
Frequently asked questions
What is a good Flesch Reading Ease score?
For writing aimed at the general public, 60–70 or higher is a good target; it corresponds to plain English. Academic and legal texts often score below 30.
Why do different readability tools give different scores?
They detect sentences and estimate syllables in slightly different ways, and small differences in those counts shift the formulas. Compare scores from the same tool over time.
What grade level should I aim for?
Around grade 8 suits most audiences, including web content and business writing. Go lower for health or safety information and for readers learning English.
Does it work for languages other than English?
The formulas were built and tested on English, so scores for other languages are only rough indications. The tool shows a warning when your text is mostly non-English letters.
Is my text saved or uploaded?
It is not uploaded. The analysis runs in your browser, and your latest text is kept only in this browser’s local storage until you clear it.