What is a readability score and why does it matter?
A readability score is a number that tells you how easy or difficult a piece of writing is to read. The most widely used formula — and the one this tool uses — is the Flesch Reading Ease scale, developed by Rudolf Flesch in 1948. It produces a score between 0 and 100. The higher the number, the easier the text is to read. A score of 60 to 70 is considered standard for general audiences, while scores below 30 indicate content that only university graduates are likely to read comfortably.
Knowing your readability score matters for several reasons. For content writers and bloggers, it's a direct signal of how accessible your content is to the average reader. For SEO professionals, it's increasingly relevant — Google's quality guidelines consistently emphasise that content should be written for people, not search engines, and overly complex writing often signals low-quality, over-optimised copy. For educators and researchers, readability scores help match written material to the appropriate reading level of an audience.
The two scores this tool calculates
Flesch Reading Ease score
The Flesch Reading Ease test gives you a score from 0 to 100 based on two factors: the average number of words per sentence, and the average number of syllables per word. Shorter sentences and simpler words produce higher scores. The formula is:
Score = 206.835 − (1.015 × words per sentence) − (84.6 × syllables per word)
To put this in context — a score of 90 or above is considered very easy, the kind of language used in children's books or simple instructions. A score of 60 to 70 is the sweet spot for most web content: readable by the general public, clear without being patronising. Below 30 is university-level material — dense, technical, and slow to process for most readers.
Flesch-Kincaid Grade Level
The Flesch-Kincaid Grade Level score translates the same inputs into an approximate US school grade level. A score of 8 means an eighth-grader should be able to read and understand the text. A score of 12 means high school level. This score is particularly useful if you're writing for a specific educational context or if you've been given a reading level target for your content — for example, many government and health websites aim for a Grade 6 to 8 level to maximise public accessibility.
Note that the grade level score has no upper limit — very complex technical writing can score 15, 18, or even higher, which simply means the text is significantly above standard high school reading level.
How to use this readability checker
Using the tool is straightforward. Paste your text into the box above — it could be a blog post, an email, a product description, an essay, or any other piece of writing. Click "Check readability" and within a second you'll see:
- Your Flesch Reading Ease score and what it means in plain English
- Your Flesch-Kincaid Grade Level score
- Total word count, sentence count, and syllable count
- A visual indicator showing where your score sits on the scale
- A highlighted reference table showing your score band
- If your score is below 80, suggested word replacements to help improve clarity
Everything runs in your browser — your text is never sent to any server. You can paste sensitive drafts, confidential documents, or unpublished content without any privacy concerns.
Readability and SEO — what's the connection?
Google has never published a specific readability score for SEO as a direct ranking factor, but the indirect connection is well-established. Here's why it matters for search performance:
Bounce rate and engagement
If a reader lands on your page and finds the content difficult to follow, they leave. High bounce rates signal to Google that the page isn't satisfying the searcher's intent, which can suppress rankings over time. Content with a Flesch Reading Ease score in the 60–70 range consistently performs better on engagement metrics because more people actually read it.
Featured snippets and voice search
Google's featured snippets — the answer boxes that appear at the top of search results — overwhelmingly favour concise, clearly written text. The same applies to voice search results, which are almost always taken from content with a high reading ease score. If you want your content to appear in these positions, writing clearly and simply is one of the most direct paths to getting there.
Content quality signals
Pages flagged as low quality by Google's quality raters often share characteristics with low readability scores: very long sentences, excessive use of complex vocabulary, dense paragraphs with no visual breaks. Running your content through a readability test online before publishing is a quick way to catch these patterns before they affect your rankings.
Readability benchmarks by content type
Different types of content have different readability expectations. Here's a practical guide:
- Blog posts and articles — aim for a Flesch score of 60–70. This is the standard for general web content and what most content guidelines recommend.
- Landing pages and product descriptions — aim for 70+. Commercial copy benefits from being as clear and frictionless as possible. The easier to read, the easier to convert.
- Email newsletters — 65–75 is ideal. People skim emails, so short sentences and simple words keep them reading.
- Academic writing — 30–50 is the normal range. Academic audiences expect and can handle greater complexity, but unnecessarily dense writing still slows comprehension.
- Legal and medical content — even here, aiming for 50+ where possible improves accessibility without compromising accuracy.
- Children's content — 80–100. Simple vocabulary, very short sentences, familiar words.
Frequently asked questions
Yes, completely free. No account needed, no word limits, no paywalls. Paste as much text as you like and check as often as you need.
The formula is: 206.835 minus (1.015 × average words per sentence) minus (84.6 × average syllables per word). Shorter sentences and simpler vocabulary produce higher scores. The tool counts your words, sentences, and syllables automatically — you just need to paste your text.
For most general web content, a Flesch Reading Ease score of 60 to 70 is considered good for SEO. This equates to a Flesch-Kincaid Grade Level of around 8 to 9, which means the content is accessible to most adult readers. Scores above 70 are even better for content targeting a broad audience.
No. All calculations happen in your browser using JavaScript. Your text never leaves your device. This makes the tool safe to use with confidential drafts, client documents, or any sensitive writing.
The Gunning Fog Index is another readability formula that estimates the years of formal education needed to understand a piece of text on first reading. It's similar to the Flesch-Kincaid Grade Level but uses a different calculation that focuses on the proportion of complex (three-or-more syllable) words. Our tool currently focuses on the Flesch formulas, which are the most widely used in content and SEO work.
Grammar checkers like Grammarly look for errors — incorrect punctuation, wrong verb tense, misspellings. A readability checker doesn't look for errors at all. It measures how complex the correct text is. Your text can be grammatically perfect and still score very low on readability because of long, complicated sentences. The two tools serve different purposes and work best used together.