Split long sentences
Look for sentences that join two full thoughts with "and", "but", "which" or "because". Make them two sentences. Sentence length is a large part of every formula, so this usually moves the score most.
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FREE TOOL
Readability Score Checker: Flesch, Grade Level and AI Readability
A readability score checker measures how easy a piece of text is to read. Paste your content and this tool reports Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog Index, SMOG Index and reading time, then lists the sentences that are hardest to read and the fixes to make first. It also checks seven signals for how clearly AI answer engines can pull sentences from your text.
Check your text now or keep reading to understand what each score means.
Use the toolQuick start
1Paste your text
2Click Analyse Readability
3Read the score breakdown
4Open the sentence analysis
Paste your content below
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Works best with 100 or more words. Short snippets like headlines will give limited results.
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Score breakdown
AI readability signals
How well AI engines like ChatGPT, Perplexity, and Google AI Overviews can extract and cite this content
Sentence analysis
Priority fixes
0 to 100, higher is easier. 60 to 70 is plain English. Flesch-Kincaid Grade: the US school grade needed to follow the text. Gunning Fog and SMOG: years of education needed, based on long words. To raise your score: shorten sentences and use shorter words.
What Is a Readability Score?
A readability score is a number that estimates how easy a text is to read. Most formulas use two things: how long the sentences are and how long the words are. Long sentences full of long words score as hard. Short sentences with common words score as easy.
The best-known measure is Flesch Reading Ease, which runs from 0 to 100. A higher number means easier text. Other formulas, such as Flesch-Kincaid, give a US school grade level instead, where a lower number means easier text.
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How to Use the Readability Score Checker
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1STEP 1 Paste your text. The page suggests 100 words or more. Very short snippets give limited results.
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2STEP 2 Click Analyse Readability. You get an overall score out of 100.
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3STEP 3 Read the score breakdown for each formula and the reading time.
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4STEP 4 Open the sentence analysis to see which sentences are flagged.
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5STEP 5 Work through the priority fixes, edit your text, then analyse it again.
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6STEP 6 Copy the report if you want to share it with a writer or editor.
Expert tip
Use the tool
Check the body text only. Menus, captions and code samples pasted with the article distort the sentence count and the score.
The Five Readability Measures
| Measure | What it gives | Based on | Often used for |
|---|---|---|---|
| Flesch Reading Ease | Score from 0 to 100 | Words per sentence and syllables per word | Web copy, blogs, email |
| Flesch-Kincaid Grade Level | US school grade | Words per sentence and syllables per word | Education, public information |
| Gunning Fog Index | Years of education | Sentence length and words of three or more syllables | News and business writing |
| SMOG Index | Years of education | Words of three or more syllables per sentence | Health information |
| Reading time | Minutes | Word count | Planning and page experience |
No single formula is the final word. Each one weighs sentence length and word length a little differently, so the grades can differ by a point or two. Look at them together and watch the direction of change as you edit.
How the Formulas Work
Flesch Reading Ease is 206.835 minus 1.015 times the average words per sentence, minus 84.6 times the average syllables per word. Flesch-Kincaid Grade Level is 0.39 times the average words per sentence, plus 11.8 times the average syllables per word, minus 15.59.
Gunning Fog is 0.4 times the sum of the average sentence length and the percentage of words with three or more syllables. SMOG counts words of three or more syllables across the sentences and scales the result to a grade.
All four depend on counting syllables, which software estimates from spelling. Different tools count some words differently, so expect small gaps between this checker and others.
Flesch Reading Ease Score Guide
| Score | Level | Approximate US grade |
|---|---|---|
| 90 to 100 | Very easy | 5th grade |
| 80 to 90 | Easy | 6th grade |
| 70 to 80 | Fairly easy | 7th grade |
| 60 to 70 | Standard, plain English | 8th to 9th grade |
| 50 to 60 | Fairly difficult | 10th to 12th grade |
| 30 to 50 | Difficult | College |
| 0 to 30 | Very difficult | College graduate |
These bands come from Rudolf Flesch's original scale. For general web content, 60 to 70 is a common target. Specialist or technical writing often scores lower, and that can be fine if your readers are specialists.
Readability and AI Answer Engines
AI answer engines such as ChatGPT, Perplexity and Google AI Overviews build answers from passages of text. A sentence that states one clear fact and makes sense on its own is easier to lift and quote than a long sentence that depends on the paragraph around it.
The AI readability section of this tool checks seven signals of that kind. Treat them as editing guidance. No tool can promise that an AI system will cite a page, and these engines do not publish their selection rules.
- Keep key definitions and facts in short, complete sentences.
- Name the subject. "The report found" is clearer than "it was found".
- Use the plain word where it carries the same meaning.
- Put the answer first, then the detail.
For a wider check of answer-engine readiness, run the same text through the AEO readiness checker.
How to Improve Your Readability Score
Choose shorter words
Swap "utilise" for "use", "facilitate" for "help" and "approximately" for "about". Keep technical terms your readers need, and explain them once.
Prefer active voice
"The team wrote the report" is shorter and clearer than "The report was written by the team". Passive voice is fine when the doer is unknown or unimportant.
Vary sentence length
A run of very short sentences can feel choppy. Mix short and medium sentences, and keep the long ones for explanation.
Lead with the main point
Put the most important information at the start of the paragraph. Readers who scan will still get it.
Common Mistakes
- Chasing a number. A high score does not make text accurate, useful or well organised.
- Writing down to expert readers. Match the level to the audience.
- Testing a few lines. Short samples swing wildly. Use a full section or article.
- Including headings, lists and code. They confuse sentence detection.
- Comparing scores from different tools. Use one tool for before and after.
Limits of This Readability Checker
- The formulas were built for English. Scores for other languages are not reliable.
- They measure sentence and word length, not meaning, structure, design or accuracy.
- Syllable counts are estimates.
- Readability is not a confirmed Google ranking factor. Clear writing helps readers, which is the reason to do it.
- The AI readability signals are heuristics and do not predict citations.
Privacy
The live page states that the checker runs in your browser. Even so, avoid pasting confidential documents into any online tool unless you have to.
Related Content Tools
Count words and reading time with the word counter. Check keyword use with the keyword density checker. Review trust signals with the E-E-A-T score checker and answer-engine readiness with the AEO readiness checker. To rework hard sentences, try the AI rewriter.
Frequently Asked Questions
What is a good readability score?
For general web content, a Flesch Reading Ease score of 60 to 70 is a common target. That is plain English at about an 8th to 9th grade level. Specialist content can reasonably score lower.
What is the difference between Flesch Reading Ease and Flesch-Kincaid Grade Level?
Both use sentence length and syllables per word. Reading Ease gives a 0 to 100 score where higher is easier. Grade Level gives a US school grade where lower is easier.
Does readability affect Google rankings?
Google has not confirmed readability scores as a ranking factor. Clear writing can still help, because people are more likely to read, understand and use the page.
Why do I get different scores in different tools?
Tools count syllables and detect sentence ends in slightly different ways. Use the same tool before and after editing.
How much text do I need?
The page suggests at least 100 words. Longer samples give steadier scores.
Why does the tool show several scores?
Each formula weighs sentence length and word length differently. Seeing them together gives a fuller picture than one number.
What are the AI readability signals?
Seven checks of how clearly sentences can be extracted and quoted by AI answer engines. They are guidance for editing, not a prediction of citations.
Does it work for languages other than English?
The formulas were designed for English, so results for other languages are not reliable.
Is my text sent to a server?
The live page states that the tool runs in your browser. Check your readability score
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