Free Readability Checker
Write content people will actually read.
Readability is one of those things that sounds boring until you realise it’s actually the whole game. If someone can’t understand what you’ve written, none of the rest of it matters. Not your SEO, not your strategy, not the hours you spent agonising over the headline. They’ll just leave.
I’ve spent the last decade or so writing for clients across every industry I can think of, from law firms to brewing equipment manufacturers, and the pattern is always the same. The pieces that actually work are the ones that respect the reader’s time. Short sentences. Plain words. Ideas that build on each other instead of tripping over themselves.
That’s why I built this. It pulls together six of the most respected readability formulas, runs them all at once, and translates the results into something that actually means something. UK reading ages. Audience size estimates. A clear verdict on whether your content is going to land or fall flat.
Paste your text. See where you stand. Make it better.
Rob, Wrise
Why readability matters more than you think
Readability isn’t an academic exercise. It’s one of the most practical levers you have for improving how content performs. Here are four reasons it’s worth paying attention to, whether you’re writing a landing page, a blog post, or an email campaign.
Readable content converts
Short sentences and plain language make it easier for readers to follow your argument and reach your call to action. The harder you make them work, the less likely they are to act.
It affects your SEO
Google doesn’t use readability as a direct ranking factor, but readable content reduces bounce rates and increases dwell time. Most top-ranking pages are written at a Year 7 to Year 9 level.
It shapes how AI cites you
Google’s AI Overviews and tools like ChatGPT surface and cite content that’s clear and well-structured. Dense, jargon-heavy writing is harder to parse and less likely to be referenced.
It widens your audience
The average UK reading age is around Year 9, and 85% of UK adults read at Grade 6 or above. Writing at this level isn’t dumbing down. It’s opening up.
Want to go further? Our affordable SEO packages are built for small businesses that want real rankings, not just readable content.
What counts as a good readability score?
Readability scores use US grade levels, but converting them to UK equivalents is straightforward: add 1 to get the equivalent UK school year. So a Grade 8 score equals UK Year 9, which corresponds to ages 13 to 14.
For marketing content aimed at a general UK audience, aim for a Flesch Reading Ease score of 60 to 70. That’s the sweet spot for reaching the widest possible audience while still sounding professional. The table below shows how each score band maps to a reading level and the kind of content it typically represents.
| Flesch Score | US Grade | UK Year | Age | Difficulty | Typical examples |
|---|---|---|---|---|---|
| 90 to 100 | Grade 1 to 2 | Year 2 to 3 | 6 to 8 | Very easy | Children’s books, simple instructions |
| 80 to 90 | Grade 3 to 4 | Year 4 to 5 | 8 to 10 | Easy | Comics, basic consumer content |
| 70 to 80 | Grade 5 to 6 | Year 6 to 7 | 10 to 12 | Fairly easy | Tabloid newspapers, marketing emails |
| 60 to 70 | Grade 7 to 8 | Year 8 to 9 | 12 to 14 | Standard | Most websites, blogs, news articles |
| 50 to 60 | Grade 9 to 10 | Year 10 to 11 | 14 to 16 | Fairly difficult | Broadsheet newspapers, GCSE content |
| 30 to 50 | Grade 11 to 13 | Year 12 to 13 | 16 to 18 | Difficult | Professional reports, A-level content |
| 0 to 30 | Grade 14+ | Degree level | 18+ | Very difficult | Academic journals, legal documents |
For most marketing content (blog posts, landing pages, email campaigns), aim for the 60 to 70 range. If you’re writing advertising copy or consumer-facing communications, push higher. The simpler and more direct your writing, the better it tends to perform.
Understanding the six readability formulas
The tool runs six established readability formulas. Each one measures your content slightly differently. Here’s what each score means and when it’s most useful.
Flesch Reading Ease
The most widely used readability test. Produces a score between 0 and 100, with higher meaning easier. A score of 60 to 70 is plain English and suits most UK adult audiences. The best all-round score for general web and marketing content.
Flesch-Kincaid Grade
Converts Flesch readability into a US school grade level. Add 1 to get the UK school year. A score of 8 equals UK Year 9 (ages 13 to 14). Weights sentence length more heavily than the Flesch Reading Ease score.
Gunning Fog Index
Measures how many years of education a reader needs to understand your text on first reading. Places particular weight on long words with three or more syllables. A score below 12 (UK Year 13) is generally accessible to adult readers.
SMOG Grade
Recommended by the NHS for health and public sector content. Counts polysyllabic words (three or more syllables) and is one of the most accurate formulas for predicting comprehension. Works best with 30 sentences or more.
Coleman-Liau Index
Based on the number of characters per word rather than syllables. This makes it particularly consistent and easy to calculate. Add 1 for the UK year equivalent. Tends to give slightly higher scores than Flesch-Kincaid for technical content.
Automated Readability
Like Coleman-Liau, ARI uses character count rather than syllables. Originally developed for typewriters where syllable counting wasn’t practical. Add 1 for the UK equivalent school year. Aligns closely with Flesch-Kincaid.
UK readability targets by content type
Different types of content have different readability targets. Here’s a quick reference guide based on UK conventions.
| Content type | Target Flesch score | Notes |
|---|---|---|
| General websites and blogs | 60 to 70 | Accessible to around 85% of UK adults |
| Marketing and advertising copy | 70+ | Simpler, more direct copy converts better |
| Email marketing | 60+ | Short sentences and conversational tone outperform formal copy |
| NHS and public health content | 70+ (SMOG preferred) | Recommended reading age of around 11 (Year 6 to 7) |
| GOV.UK and public sector | 80+ | Recommended reading age of 9 years old (Year 4 to 5) |
| Legal and financial (consumer) | 50 to 60 minimum | Growing regulatory pressure to simplify consumer documents |
Who uses a readability checker?
Readability scores are used by a wide range of professionals across the UK. Here’s a snapshot of the people who rely on them most.
SEOs
Use readability scores to make sure on-page content engages target audiences. Readable content reduces bounce rates and lifts dwell time, both of which support stronger organic rankings.
Content marketers
Use readability checks across campaigns, landing pages, and lead magnets to keep messaging clear and on-brand. Simpler content tends to convert better and earn more shares.
Bloggers
Use readability tools to keep posts engaging and easy to skim. Whether you’re a freelance writer or running your own site, working with experienced blog writers or checking your own drafts helps keep readers on the page.
Copywriters and brand teams
Use readability tools to keep messaging sharp and accessible, particularly when writing for a broad consumer audience where clarity is key to conversion.
PR and comms professionals
Use readability scores to make sure press releases, reports, and public statements stay clear and accessible to the widest possible readership.
NHS and public health writers
Use SMOG scores in particular to make sure patient information, leaflets, and website content can be understood by the widest possible audience, including those with lower literacy levels.
Legal and compliance teams
Use readability checkers when simplifying contracts, terms and conditions, and consumer-facing documents, particularly in regulated industries like financial services and insurance.
Teachers and educators
Use readability tools to assess whether reading materials are appropriate for their pupils’ age and ability level, and to choose age-appropriate texts for the curriculum.
Frequently asked questions
What is a good readability score for marketing content?
For most marketing content, including blog posts, landing pages, and email campaigns, aim for a Flesch Reading Ease score of 60 to 70. This level is accessible to around 85% of UK adults and is considered plain English. For advertising copy or direct response content, aim for 70 or above. The simpler and more direct your writing, the better it tends to convert.
Does readability affect SEO?
Not directly. Google doesn’t use readability as a confirmed ranking signal. However, readable content indirectly improves your SEO by reducing bounce rates, increasing dwell time, and encouraging return visits and social sharing. These engagement signals are factors Google does take into account. Content written at a Grade 6 to 8 level (UK Year 7 to 9) consistently performs well in organic search.
Does readability affect how AI and LLMs use my content?
Yes. AI search tools and large language models such as ChatGPT, Google’s AI Overviews, and Perplexity are more likely to surface, summarise, and cite content that is clear and well-structured. Dense or jargon-heavy writing is harder for these systems to parse and is less likely to be referenced in AI-generated responses. Writing for readability is increasingly important for AI-driven search visibility.
What is the difference between Flesch Reading Ease and Flesch-Kincaid Grade Level?
Both formulas were developed by Rudolf Flesch and use the same inputs (sentence length and syllables per word) but they produce different outputs. Flesch Reading Ease produces a score between 0 and 100 (higher is easier). Flesch-Kincaid Grade Level converts the same data into a US school grade level, which you can convert to a UK school year by adding 1. For most purposes, the Flesch Reading Ease score is easier to interpret at a glance.
What is a good readability score for a website?
For most UK websites, aim for a Flesch Reading Ease score of 60 to 70, which equates to approximately Grade 7 to 8 or UK Year 8 to 9 (ages 13 to 14). This level is accessible to around 85% of UK adults and is considered plain English. If your audience includes people with lower literacy levels, such as a general consumer audience or public sector content, aim for 70 or above.
What readability level does GOV.UK recommend?
GOV.UK’s content design guidelines recommend writing for a reading age of 9 years old, approximately UK Year 4 to 5 or Grade 3 to 4. Their research found that plain, simple English is preferred by all readers regardless of education level, and that complex content causes people to disengage or lose trust.
How do I convert a US grade level to a UK school year?
Add 1 to the US grade level. For example, Grade 5 equals UK Year 6 (ages 10 to 11), Grade 8 equals UK Year 9 (ages 13 to 14), and Grade 11 equals UK Year 12 (ages 16 to 17). The tool above does this conversion automatically for every score.
Why does my text score differently across the six formulas?
Each formula uses a slightly different method to calculate readability. Some weight sentence length more heavily, others focus on word complexity or character count. It is normal for scores to vary between formulas. The grade level consensus section shows all five grade-level scores together so you can see the overall picture rather than relying on any single formula.
Can I use this tool for free?
Yes. This readability checker is completely free to use, with no word limits, no sign-up required, and no restrictions on how many times you use it. Take it for a spin.