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Readability score calculator

Five readability formulas at once: Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau. Plus a sentence-by-sentence breakdown.

60 words · 4 sentences10 complex (3+ syllables)
Flesch Reading Ease
Standard · 8th–9th grade
61.9
Flesch-Kincaid Grade
U.S. grade level
8.4
Gunning Fog
Years of schooling
12.7
SMOG
Years of schooling
12.2
Coleman-Liau
U.S. grade level
10.7
Long sentences (≥ 25 words)
  • None — your prose flows.

Why readability matters for SEO

Google has no 'readability score' ranking factor — but readability still shapes rankings through behavior. When a page is hard to read, visitors bounce back to the search results faster, scroll less, and convert worse. Those engagement patterns are exactly what Google's systems are tuned to notice.

There's also a relevance angle: search results tend to cluster around a reading level that matches the query's audience. A graduate-level essay aimed at a beginner question is mismatched, no matter how accurate it is. Writing to the level your readers actually expect keeps them on the page — and that is the signal that moves.

The five readability formulas, explained

No single formula is definitive — each measures complexity a little differently, so this tool runs all five and you read the consensus.

  • Flesch Reading Ease — a 0–100 score; higher is easier. 60–70 is the sweet spot for general web content.
  • Flesch-Kincaid Grade — converts that ease score into a U.S. school grade level.
  • Gunning Fog — estimates the years of education a reader needs, weighting 'complex' (3+ syllable) words.
  • SMOG — a grade estimate built specifically around complex-word count; popular for health content.
  • Coleman-Liau — uses characters per word instead of syllables, so it's robust on unusual vocabulary.

How to improve a low readability score

Readability formulas reward two things above all: shorter sentences and shorter words. The fastest gains come from sentence length, so this tool also flags every sentence of 25 words or more.

Split run-on sentences at their natural 'and' or 'but' seam. Swap multi-syllable words for plain ones — 'use' over 'utilize', 'help' over 'facilitate'. Prefer the active voice, cut filler phrases, and break dense paragraphs into shorter ones. None of this dumbs down your argument; it just removes the friction between your point and the reader.

FAQ

What's a good readability target for SEO?+

For general consumer content, aim for Flesch Reading Ease ≥ 60 (8th-grade level). Technical content can go lower. The actual signal isn't the score — it's that Google rewards content matching the average reading level of the SERP, and most SERPs land between 7th and 10th grade.

Why do the scores disagree?+

Each formula counts different things. Flesch uses syllables per word, Coleman-Liau uses characters per word, SMOG uses complex words per sentence. Use the median across them as your working number.

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