A landing page gets thousands of visits and almost nobody scrolls past the second paragraph. The writing isn't wrong, exactly — it's just dense enough that reading it feels like work. Readability scores exist to catch that problem before it costs you readers, by measuring, mathematically, how much effort a piece of text demands from the person reading it.
What Is a Readability Score?
Readability scores use mathematical formulas to estimate the education level required to easily understand a piece of text. They analyze factors like average sentence length, average word length (syllables), the percentage of complex words, and the use of passive voice. The result is typically expressed as either a grade level or a 0-100 score. Lower grade level means easier to read; a higher Flesch Reading Ease score also means easier to read — the two scales run in opposite directions, which trips people up the first time they see both side by side.
Common Readability Formulas
| Formula | What It Measures | Scale |
|---|---|---|
| Flesch Reading Ease | Sentence + word length | 0-100 (higher = easier) |
| Flesch-Kincaid Grade | US grade level | Grade 1-18 |
| Gunning Fog Index | Complex word density | Grade level |
| SMOG Index | Polysyllabic words | Grade level |
| Coleman-Liau Index | Characters per word | Grade level |
Most readability tools report several of these scores at once. Flesch Reading Ease and Flesch-Kincaid Grade Level are the two most widely referenced, and they're derived from the same underlying sentence-length and syllable-count data, just scaled differently.
Target Scores for Different Content Types
Flesch Reading Ease targets: 90-100 (Very Easy — 5th grade, conversational) fits children's content and simple instructions. 70-80 (Easy — 7th grade) fits consumer-facing web content and blogs. 60-70 (Standard — 8th-9th grade) fits newspapers and most general web content. 50-60 (Fairly Difficult — 10th-12th grade) fits business writing and some academic material. 30-50 (Difficult — college level) fits technical content and legal writing. Under 30 (Very Difficult) is typical of academic papers and government documents.
💡 Most successful content creators aim for a Flesch Reading Ease of 60-70 — roughly a 7th-9th grade level. That band covers most major newspapers, popular blogs, and marketing copy, even material aimed squarely at highly educated audiences. Writing simply isn't the same as writing down to people; it's what makes complex ideas actually land.
Plain Language Isn't Just a Best Practice — It's Federal Law
It's easy to treat readability as a nice-to-have content guideline, but in the US it's also a legal requirement for a huge swath of government writing. The Plain Writing Act of 2010 requires federal executive agencies to write public-facing documents — benefit applications, tax instructions, compliance notices — in language the public can actually understand, and every covered agency has to publish an annual compliance report. The law explicitly puts the burden of clarity on the writer, not the reader: if a form is confusing, that's treated as the agency's failure, not the citizen's. It's a useful reframe for any writer — confusing copy is a writing problem to fix, not a reading-comprehension problem to blame on the audience.
How to Improve Your Readability Score
- Shorter sentences: aim for 15-20 words on average; split long sentences into two
- Simpler words: "use" instead of "utilize," "show" instead of "demonstrate," "help" instead of "facilitate"
- Active voice: "The team completed the project" rather than "The project was completed by the team"
- Vary sentence length: short, punchy sentences create rhythm; longer sentences provide context and detail when it's genuinely needed
- Subheadings: break content into scannable sections — this improves perceived readability even when the underlying sentences don't change
- White space: short paragraphs (3-4 sentences max for web) are easier to read on a screen than on paper
Readability and SEO Performance
Google doesn't use readability scores as a direct ranking factor, but readability strongly influences the metrics Google does measure: dwell time (readable content keeps people on the page longer), bounce rate (confusing content drives immediate exits), social shares (clear content gets shared more often), and backlinks (authoritative, readable content earns more of them naturally). Yoast SEO, the popular WordPress plugin, bundles readability analysis alongside its keyword optimization checks for exactly this reason — the two have always been closely linked in practice, even without a direct algorithmic connection.
Quick Checklist
- Aim for Flesch Reading Ease of 60-70 for most web content and blogs
- Keep average sentence length under 20 words
- Replace complex words with simpler equivalents wherever possible without losing precision
- Write in active voice — passive voice reduces readability and engagement
- Use subheadings every 200-300 words to break up long content for scanning
- Vary paragraph length — 1-sentence paragraphs create emphasis; 3-4 sentence paragraphs for normal content
For informational purposes only. Not financial, tax, or legal advice. Consult a qualified professional before making major decisions.