What is a good readability score?

For general web content (blog posts, landing pages, product copy) aim for a Flesch-Kincaid Reading Ease above 60 and a Gunning Fog Index below 12. That maps to roughly a 7th–8th grade reading level, which is where the average adult reader is most comfortable on a screen.

What readability score does Google prefer?

Google has never confirmed a target readability score as a direct ranking factor. But readability affects every metric Google does measure: dwell time, bounce rate, scroll depth, and pogo-sticking. Pages written at a grade 7–8 level consistently outperform pages written at grade 12+ in these engagement signals, which in turn correlate strongly with rankings.

How is the Flesch-Kincaid score calculated?

Flesch-Kincaid Reading Ease uses the formula: 206.835 − 1.015 × (words/sentences) − 84.6 × (syllables/words). Long sentences and syllable-heavy words drag the score down. The companion Flesch-Kincaid Grade Level uses a different formula to output a US grade level instead of a 0–100 scale.

What is the Gunning Fog index?

The Gunning Fog Index is calculated as 0.4 × ((words/sentences) + 100 × (complex words/words)), where a complex word is one with three or more syllables. The result is the number of years of formal education a reader needs to understand the text on the first pass. A score of 8 means an 8th-grader can read it; 16 means a college graduate is required.

Can I check the readability of a URL, not just text?

Yes. Switch to the 'Enter URL' tab, paste any public URL, and we'll fetch the page, strip the navigation and footer, and score only the readable body content. This is how you compare your published page against the version you have in draft.

Is this readability checker free?

Yes. No login, no credit card, no hidden trial. We rate-limit URL checks to 30 per minute per IP to keep the service fast for everyone. Text-mode is unlimited.

What's the difference between readability and reading level?

Readability is the overall ease of reading: it includes sentence rhythm, word choice, and structure. Reading level is a specific output: a single grade-level number (e.g. 'grade 8'). Reading level is one component of readability. A page can have a low grade level but still feel awkward to read if its structure is poor.

Readability Checker

Paste your text or enter a URL to get your readability score instantly. Flesch-Kincaid, Gunning Fog, a letter grade, and SEO advice in one report.

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Readability checker

Here's how it works:

Add your text or URL to get an instant readability score.
Check the red and orange highlights to see the sentences hurting your score.
Rewrite or shorten them and the score updates live as you edit.

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What is a readability score?

A readability score is a number that estimates how easy a piece of writing is to understand. The two algorithms behind every modern checker (Flesch-Kincaid and Gunning Fog) both look at the same two things: how long your sentences are, and how many syllable-heavy words you use.

Higher Flesch scores mean easier reading; lower Gunning Fog values mean fewer years of education needed. Together they map your text to a US grade level, so you can tell at a glance whether you're writing for a 5th-grader or a graduate student.

For most SEO content (blog posts, landing pages, product descriptions) you want a Flesch score above 60 and a grade level around 7–8. That's the level the average web reader scans comfortably on a phone.

How to use this readability checker

Three steps. No login. No limits on text-mode.

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Step 1: Paste your text or enter your URL
Either paste any text into the editor for instant client-side scoring, or switch to URL mode to score a published page. URL mode fetches your page, strips the chrome, and scores only the readable body content.
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Step 2: Read your scores
You'll see a letter grade, both Flesch-Kincaid Reading Ease and Gunning Fog Index, and a sentence-by-sentence highlight. Red and orange sentences are where most rewrites happen.
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Step 3: Improve your content
Break long sentences. Swap complex words for simpler synonyms. Cut adverbs. Re-check until your grade level drops to 7 or 8, where most web content lives.

How to interpret your readability score

Flesch-Kincaid Reading Ease runs from 0 (impossible to read) to 100 (a 5th-grader could read it).

Score	Grade	Meaning	Best for
90–100	Grade 5	Very easy	General public, conversational content
70–89	Grade 6–7	Easy	Blog posts, landing pages, marketing copy
50–69	Grade 8–10	Standard	Business writing, news articles
30–49	Grade 11–12	Difficult	Academic, technical documentation
0–29	College+	Very difficult	Specialist or scholarly audiences

Flesch-Kincaid vs Gunning Fog: what's the difference?

Both algorithms estimate reading difficulty, but they weight different signals. Showing both side by side gives a more reliable picture than relying on one score alone.

Metric	Flesch-Kincaid	Gunning Fog
Scale	0–100 (higher = easier)	Years of education needed
Inputs	Avg sentence length + avg syllables/word	Avg sentence length + % complex words (3+ syllables)
Best for	General web copy, marketing	Technical writing, business reports
Strength	Intuitive 0–100 scale	Direct grade-level output
Weakness	Treats all multi-syllable words equally	Counts proper nouns as complex

Why readability matters for SEO

Google doesn't publish a 'readability score' as a ranking factor, but readability shows up everywhere in the signals it does measure. A page that's hard to read pushes readers back to the search results, which is a NavBoost-quality bounce.

Content that scores at a grade 7–8 level keeps readers on the page longer, gets shared more often, and earns more natural backlinks. All three feed back into rankings over time.

The same applies to AI search: ChatGPT, Perplexity, and Google's AI Overviews extract text that's structured, scannable, and clearly written. Hard-to-parse paragraphs get skipped in favor of competitors.

If you want help rewriting low-readability pages without losing brand voice, ChatSEO scans your sitemap and writes the fix for you. Try it free, no credit card.

Frequently asked questions

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