Readability checker
Score English text with six readability formulas as you type, from Flesch Reading Ease to SMOG, and see the long sentences, hard words and passive voice that make it harder to read.
- Six formulas and an average grade
- Long sentences highlighted in your text
- Runs in your browser, nothing uploaded
Flesch Reading Ease
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- Text—Paragraphs
- Sentences—Words per sentence
- Words—Syllables per word
- Scores—Six formulas
Readability report
Audience and statistics
The checks compare your text with this target.
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Six formulas
Each one estimates difficulty from different counts.
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Your text, highlighted
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What readability scores measure
Readability formulas estimate how hard a text is from two things they can count: how long the sentences are and how long the words are.
Sentence length
Long sentences make readers hold more in mind at once. Every formula rises with the average number of words per sentence.
Word length
Syllables, letters or words of three or more syllables stand in for vocabulary. Long words are, on average, less common.
Grade levels
Most formulas give a US school grade: 8 means a typical 13 to 14-year-old can follow the text. Add five or six for the age.
A guide, not a verdict
Formulas cannot tell whether a text is clear, accurate or well ordered. Short words in a muddled argument still score well.
What your Flesch score means
Rudolf Flesch's original bands, with the kind of writing that usually lands in each.
| Score | Difficulty | School level | Typical writing |
|---|---|---|---|
90–100 |
Very easy | 5th grade | Children's books, simple instructions |
80–90 |
Easy | 6th grade | Conversational web copy, consumer emails |
70–80 |
Fairly easy | 7th grade | Marketing pages, newsletters |
60–70 |
Standard | 8th–9th grade | Most blog posts, news and product pages |
50–60 |
Fairly difficult | 10th–12th grade | Business and technical writing |
30–50 |
Difficult | College | Academic and specialist writing |
0–30 |
Very difficult | College graduate | Legal contracts, research papers |
The six formulas
The exact calculations the tool uses, so you can check any number yourself.
| Formula | Calculation | Result |
|---|---|---|
Flesch Reading Ease |
206.835 − 1.015 × words per sentence − 84.6 × syllables per word | 0 to 100, higher is easier |
Flesch-Kincaid Grade |
0.39 × words per sentence + 11.8 × syllables per word − 15.59 | US school grade |
Gunning Fog |
0.4 × (words per sentence + 100 × hard words per word) | Years of schooling |
Coleman-Liau |
0.0588 × letters per 100 words − 0.296 × sentences per 100 words − 15.8 | US school grade |
SMOG |
1.043 × √(polysyllables × 30 ÷ sentences) + 3.1291 | US school grade, 30+ sentences |
Automated Readability Index |
4.71 × characters per word + 0.5 × words per sentence − 21.43 | US school grade |
How to use this tool
From a draft to text your readers can follow.
Paste your text
Type, paste or open a .txt, .md or .html file. Pasted HTML and Markdown are reduced to text.
Read the scores
Six formulas and an average grade update as you type, with what each one means.
Pick your audience
The checks compare your score with a typical target for that kind of reader.
Edit the highlights
Shorten the marked long sentences and swap hard words, then watch the score move.
What this tool does, and what it doesn't
A plain list, so you know exactly what to expect.
This tool does
- Calculate six readability formulas
- Average them into one grade level
- Highlight long sentences and hard words
- Flag possible passive voice
- Estimate reading and speaking time
- Work offline once the page has loaded
This tool does not
- Send your text to our server
- Judge accuracy, tone or structure
- Rewrite or correct your text
- Score languages other than English
- Count syllables perfectly
- Raise Google rankings by itself
Where your data goes
Nowhere. Every count and score is calculated in your browser, and files you open are read on your device. Nothing you type is sent to our server or stored. Like any website, our server keeps normal access logs of page visits, as described in our privacy policy.
Why your results might look unexpected
The six situations people run into most, and what each one means.
Scores disagree
Syllable formulas and letter formulas react differently to your words. Look at the average grade.
Too many sentences counted
Headings and list items without a full stop count as sentences, which makes the text look easier.
One very long sentence
A missing full stop, or a list joined with semicolons, turns a paragraph into one sentence.
Short text, odd scores
Under about 100 words, one long sentence or word moves every score a lot.
Not English
The formulas and syllable rules are for English, so other languages get meaningless grades.
Code or URLs in the text
Long tokens raise the letter-based scores. Remove code and links before checking.
Questions about readability
What is a good Flesch Reading Ease score?
For general web content, 60 to 70 is a common target. It matches about 8th or 9th grade in the US, which most adults read comfortably. Marketing copy often aims higher, 70 to 80, while technical or academic writing usually scores lower. The right score depends on who reads your text, not on a single number.
Why do the formulas give different grade levels?
Each formula counts different things. Flesch-Kincaid and SMOG use syllables, Gunning Fog counts words of three or more syllables, and Coleman-Liau and the Automated Readability Index count letters instead. A text with short but rare words, or long but common ones, will score differently on each. The average grade evens out these differences.
Do readability scores affect Google rankings?
Not directly. Google's John Mueller said in 2018 that Google does not run basic algorithms that count words to work out a reading level. Readability still matters because people stay with text they understand. Write for your audience first, and use the score as a check, not a target to game.
How accurate are the syllable and sentence counts?
They are estimates. Syllables are counted with English spelling rules, which are right for most words but can be one off for words such as "poem" or "business". Sentences are found by the browser's sentence splitter, and lines without end punctuation, such as headings and list items, count as sentences. Over a few hundred words these small errors have little effect on the scores.
Why does SMOG say it needs 30 sentences?
SMOG was designed for samples of 30 sentences. With fewer, the tool still scales the count to 30, but the result is less reliable and is marked as such. Readability formulas in general become more stable with longer samples; below about 100 words, read every score as a rough guide.
Does it work for languages other than English?
The formulas and the syllable rules were made for English. Text in other languages will get numbers, but they do not mean the same reading level. The tool warns when much of the text is not in the English alphabet.
Is my text sent to your server?
No. The analysis runs entirely in your browser, including text from files you open, and nothing you type is sent to our server or stored. Like any website, our server keeps normal access logs of page visits, as described in our privacy policy.