Readability + SEO Scorer - Flesch Score & Check
Paste any content and get an instant readability score (Flesch), grade level, sentence-by-sentence highlighting, and a 6-factor on-page SEO audit. All in your browser, free, no sign-up.
How to use this tool
- 1Paste your content
Copy a page, blog post, product description, or any text and paste it into the box. Works best with at least 100 words.
- 2Enter your focus keyword (optional)
Add the keyword you are targeting for this page. The tool will calculate density and highlight issues.
- 3Read your scores and fix them
Your readability and SEO scores appear instantly. Hover sentences to see their grade level. Expand each SEO factor for specific, actionable advice.
What this tool measures
The gold-standard readability formula - used by US government agencies, publishers, and SEO tools worldwide. Based on sentence length and syllables per word. Score 0-100, higher = easier.
Every sentence is highlighted in one of four colours: green (easy), yellow (medium), orange (hard), red (very hard). Hover any sentence to see its word count and Flesch score.
Enter your focus keyword and the tool counts how often it appears relative to total word count. Ideal range: 0.5%-2%. Below that = weak signal; above 3% = over-optimised.
Short pages rarely rank. The tool checks whether your content meets the 800-word threshold that most competitive keywords require, and flags pages that are too thin.
Short paragraphs (under 100 words) score better for readability and featured snippet eligibility. The tool counts your paragraphs and flags walls of text.
Passive voice ("The page was written by...") is harder to read and scores lower on Flesch. The tool estimates your passive voice ratio and flags sentences to rewrite.
Why readability matters for SEO
Hard-to-read content kills dwell time
When users hit dense, complex paragraphs, they leave. Google's Core Web Vitals and user engagement signals (dwell time, scroll depth, return rate) are all downstream of how readable your content is. A Flesch score below 40 is consistently associated with above-average bounce rates for non-specialist audiences.
AI engines prefer scannable, simple text
Featured snippets, AI Overviews, and answer boxes disproportionately cite content that is easy to parse. AI language models extract answer candidates from the first sentence of clear, directly-written paragraphs. Academic prose, long subordinate clauses, and jargon all reduce your citation probability.
Google's own guidelines emphasise clarity
Google's E-E-A-T Quality Rater Guidelines specifically mention that high-quality content should be easy to understand and appropriate for the intended audience. Pages that pass Flesch 60+ consistently demonstrate that the author knows how to communicate clearly - a signal of genuine expertise.
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Frequently asked questions
What is the Flesch Reading Ease score?
A 0-100 formula that rates how easy text is to read - higher = easier. Based on average sentence length and syllables per word. 60-70 is considered standard for web content; 80+ is very easy; below 30 is academic-level prose.
What readability score should I aim for in SEO?
Aim for 60+ for most web content. Google does not directly rank by readability, but readable content earns better engagement signals (lower bounce rate, higher dwell time) and is more likely to appear in featured snippets and AI answer boxes. For specialist audiences (medical, legal, academic), 40-60 is acceptable.
What is keyword density and what is the ideal percentage?
Keyword density is how often your target keyword appears as a percentage of total word count. Aim for 0.5%-2%. Below that, the page may not register as topically relevant. Above 3%+ looks over-optimised and can trigger Google penalties. Modern SEO focuses on natural language - use synonyms and related terms rather than exact repetitions.
How do I improve my readability score quickly?
The fastest fixes: (1) Break sentences over 25 words into two. (2) Replace long words with simpler equivalents - "utilise" → "use". (3) Convert passive voice to active voice. (4) Break walls of text into 3-4-sentence paragraphs. (5) Use sub-headings every 200-300 words.
Does this tool store my content?
No. Everything runs entirely in your browser. Your content is never sent to any server. The tool uses JavaScript to run the Flesch formula and SEO checks locally on your device.